
Class B ^^bp 

Book l¥Z 



COPWliGHT DEPOSm 



Saggar ^cmt-Centennial ^eriea; 



ELIZABETHAN TRANSLATIONS FROM THE ITAL- 
IAN, By Mary Augusta Scott, Ph.D. (A.B. Vas- 
sar, 1876), Professor of English Literature in Smith 
College. 

SOCIAL STUDIES IN ENGLISH LITERATURE. 
By Laura J. Wylie, Ph.D. (A.B. Vassar, 1877), Pro- 
fessor of English in Vassar College. 

THE LEARNED LADY IN THE EIGHTEENTH 
CENTURY. By Myra Reynolds, Ph.D. (A.B. Vas- 
sar, 1880), Professor of English Literature in Chicago 
University. [/« preparation^ 

THE CUSTOM OF DRAMATIC ENTERTAINMENT IN 
SHAKESPEARE'S PLAYS. By Orih J. Hatcher, 
Ph.D. (A.B. Vassar, 1888), Formerly Associate Pro- 
fessor of Comparative Literature in Brjm Mawr Col- 
lege. \_In preparation J\ 

INTRODUCTION TO THE STUDY OF VARIABLE 
STARS. By Caroline E. Furness, Ph.D. (A.B. Vas- 
sar, 1891), Professor of Astronomy in Vassar College. 

MOVEMENT AND MENTAL IMAGERY. By Mar- 
GARET Floy Washburn, Ph.D. (A.B. Vassar, 1891), 
Professor of Psychology in Vassar College. 

BRISSOT DE V/ARVILLE : A STUDY IN THE HIS- 
TORY OF THE FRENCH REVOLUTION. By Eloise 
Ellery, Ph.D. (A.B. Vassar, 1897), Associate Profes- 
sor of History in Vassar College. 

HOUGHTON MIFFLIN COMPANY 
Boston and New York 



MOVEMENT AND MENTAL IMAGERY 



MOVEMENT 
AND MENTAL IMAGERY 

OUTLINES OF A MOTOR THEORY OF THE 
COMPLEXER MENTAL PROCESSES 



BY 

MARGAKET FLOY WASHBURN, Ph.D. 

Professor of Psychology in Vassar College 




BOSTON AND NEW YORK 

HOUGHTON MIFFLIN COMPANY 

^ht WaztMz pte^4 Cambritige 

1916 






COPYRIGHT, I916, BY MARGARET FLOY WASHBURN 
ALL RIGHTS RESERVED 

Published July iq/6 



MJG -7 1916 

©CLA437131 



PUBLISHED IN HONOR OF THE 
FIFTIETH ANNIVERSARY 

OF THE 

OPENING OF VASSAR COLLEGE 

1865-1915 



PREFACE 

The first debt of gratitude which I have to acknowledge in 
completing this book is to the Trustees of Vassar College, who 
have authorized the publication of the series to which the book 
belongs, in commemoration of the fiftieth anniversary of the 
opening of the college. I wish that I had a better contribution 
to offer in honor of my Alma Mater. My second debt is to my 
colleague. Dr. Elizabeth L. Woods, who by generous sacrifice 
of time has read through the whole manuscript and suggested 
many improvements. 

Although the problems considered in this essay are of a tech- 
nical rather than a popular character, I have tried so to present 
them that a reader without psychological training could follow 
the discussion. No topic dealt with in the book is treated in 
anything like an exhaustive manner. It is only fair to say, 
however, that if all the reading which was done in direct con- 
nection with its composition were represented in the list of 
references at the end, that list would be three times as long as it 
is. I have not aimed at a thorough presentation of the litera- 
ture of my subject, but simply at an outline development of 
my own views. The psychological reader will miss references 
to KostylefF's Le mecanisme cerebral de la pensee (Paris, 1914). 
The omission is intentional. The book did not appear until 
the framework of my theory had been erected. I have felt that 
any adequate discussion of the theories of others would occupy 
space which might better be given to the consideration of the 
bearing of facts on my own views. 

Margaret Floy Washburn. 



CONTENTS 

Introduction xi 

I. Types op Association among Movements . . . 1 
II. Movement and Consciousness 17 

III. Movement and the Image or Centrally Excited Sen- 

sation 27 

IV. Tentative Movements 48 

V. The Spontaneous Recurrence of Movements: the 

Memory After-Image and Perseveration . . 62 

VI. The Connecting Links in Movement Systems: Asso- 
ciative Dispositions 88 

Vn. Simultaneous Movement Systems ► . . . .128 

Vni. The Problem or Purpose 151 

1 IX. The Formation of New Movement Systems under 

the Influence of Problems 174 

X. Imageless Processes 185 

xi. d1ssocla.t10n 221 

References 233 

Index of Subjects 247 

Index of Names 251 



INTRODUCTION 

From the point of view of scientific investigation no two 
subjects could present a stronger contrast than the two named 
in the title of this book. Movement is the ultimate fact of 
physical science. The measurement of the direction and ve- 
locity of movements is the most satisfactory achievement of 
science, and the scientist is contented with his explanation of 
any natural phenomenon when he has reduced it to movements 
and expressed their relations in a mathematical formula. On 
the other hand, nothing could be less attractive to the scienti- 
fic investigator with such an aim than the domain of mental 
imagery, the world of imaginary objects. Mental images are 
not only removed from general observation and open to direct 
study only by the individual who experiences them, but even 
he has no satisfactory way of measuring them and reducing 
them to mathematics. 

The movements of a living being are of all forms of move- 
ments the most complicated and difficult to study. Science is 
still a long way from showing that even the movements of an 
amoeba, the simplest of animals, are merely combinations of 
the invisible movements which constitute physico-chemical 
processes. But at least the movements which an animal makes 
belong to the world of external observation; they have direc- 
tion and velocity; they are movements, although very com- 
plex ones, and an investigator like Professor Loeb can enter- 
tain the confident hope that science will some day be able to 
show their relations to the movements of lifeless things. 

It is not surprising, therefore, that since psychology under- 
took to call itself a science, there has existed a strong desire 
to connect the facts of the mind with the facts of bodily move- 
ment. There are even psychologists, who, impatient at the 
difficulties of showing the relation between mental phenomena 



xii mTRODUCTION 

and the 'behavior' or movements of the organism, have de- 
cided to abandon the attempt, to make no effort at an investi- 
gation of the inner world of sensations, images, and thoughts, 
and to confine all their energies to the study of how persons and 
animals act, how they move. For making such a decision no 
one can be blamed. A man has but one life, and if he prefers 
to invest his mental capital in an enterprise that promises 
quicker returns than are offered by the scientific study of the 
inner life, the life of the mind, he is within his rights. But he 
is ignoring a challenge, nevertheless: shall we say that here, in 
the world of conscious experiences, as distinct from the world 
of external movements, is a whole field of phenomena which 
man must leave unworked because he can borrow no tools from 
other fields? Perhaps it is the irritating consciousness of this 
challenge that has led the most extreme * behaviorist,' Pro- 
fessor Watson, actually to deny that there exists any mental 
imagery. If we are all deluded in the belief that we possess 
mental images, then evidently the behaviorist who refuses to 
study them is wise; although even under such circumstances, 
one might think, a scientific investigator would feel some 
curiosity regarding the cause of so wide-spread a delusion. 
Watson (147) seems to argue that because the facts regarding 
mental imagery are very complicated, therefore there is no 
such thing as a mental image, whereas the opposite inference 
would be quite as natural. Because Fernald (35) and Angell (5) 
have shown that the differences between individual minds 
as regards the occurrence of mental imagery are less simple 
than had been supposed, "the way," he says, "is paved for 
the dismissal of the image from psychology." But we have 
just as good reason for denying the existence of all conscious 
processes whatever as we have for denying the existence of 
mental images. An outsider, studying merely my bodily move- 
ments, would be quite as unable to explain why a certain vapor 
should affect me with the peculiar experience of the smell of 
kerosene, or why certain ether vibrations should make me see 
red, when red does not look at all like a vibration, as he would 



INTRODUCTION xiii 

be to detect the existence of purely 'imaginary' smells and 
colors in my consciousness. 

If, then, one persists in being curious about the "inner as- 
pect*' of behavior and in believing that a man's thoughts are as 
legitimate objects for scientific study as his movements; if on 
the other hand, one realizes that it is through his movements 
that man takes his place in the rest of the order of nature, then 
the proper outcome of this twofold interest is an attempt to 
show that the whole of the inner life is correlated with and de- 
pendent upon bodily movement. This attempt is everywhere 
visible in the psychological theories of the past twenty years. 
The excuse which the present essay would offer for its own 
existence is that while the facts of attention, perception, and 
emotion have had their relation to bodily movement fully dis- 
cussed, Hhere still remain many phenomena connected with the 
complexer life of the mind, the revival of past experiences and 
the construction of new thoughts and ideas, whose connection 
with motor processes has not been satisfactorily traced. Thus 
McDougall (73) can challenge the believers in a parallelism 
between mental and physical processes to show that certain 
forms of memory can possibly be due to associations between 
movements. Even the relation of consciousness itself to move- 
ment is not yet clearly conceived. 

Nothing could be less dogmatic than the spirit iii which this 
sketch of a motor theory of mental processes is put forward. 
There are grave dangers attending the attempt to form a com- 
plex and self-consistent theory where an appeal to fact is not 
possible at every step; and one of the chief dangers is that of 
taking self-consistency as equivalent to truth, of thinking that 
a subordinate hypothesis, for instance, must be true because 
it fits nicely with the rest of the theory, even though the whole 
structure be hung up in the air. And yet in psychology espe- 
cially, it seems to me, one may be permitted to push theory 
ahead of fact. For clearly the phenomena of the mind are 

1 See e.g., Ribot (116, 117), Lange (66), MUnsterberg (94. 95), James (57), 
Judd (60). 



xiv INTRODUCTION 

enormously complicated. When a psychologist records the 
results of an experimental research, he usually analyzes them 
only from the point of view that he had in making the re- 
search: it is so difficult to analyze them at all that he has no 
time to do more. Thus he may practically throw away as 
worthless for his purpose material that to another investigator 
would be highly important. Hence a person with a theory to 
test nearly always has to make his own experiments: he looks 
through the literature in vain, for the men who might easily 
have observed the phenomenon in which he is interested over- 
looked the data bearing upon it because their own interest was 
elsewhere. The result is that the theories which get tested 
by experiment are usually theories covering a relatively small 
field; no one person in a lifetime could establish by experiment 
a complete theory of the motor basis of all mental processes. 
Yet there is an advantage to be gained by the attempt to con- 
struct such a theory: its failures and shortcomings especially 
may be helpful. The hypotheses developed in this book are 
not only often impossible to test experimentally, but may even 
be contradicted by known facts which I have overlooked. And 
yet I think the labor of writing the book will not have been 
wholly wasted if here and there a suggestion or a warning is 
derived which is of use to psychological theory. 

The points where I have departed most from what is gen- 
erally recognized as orthodox psychological doctrine are per- 
haps the theory regarding the physiological basis of central 
excitation, and the attempt to utilize, as actual causal mechan- 
isms, certain motor processes which have been neglected by 
psychological theory as mere incidental phenomena. The most 
important of these neglected motor processes are the slight 
actual muscular contractions which accompany all attentive 
consciousness and are the basis, I believe, of all associative 
activity. Another motor process to which I have assigned a 
leading function is the attitude of activity or strain charac- 
teristic of strong attention, which I believe actually constitutes 
the essence of a problem idea. 



INTRODUCTION xv 

The first step, evidently, towards working out the hypothe- 
sis that all association is association between movements is to 
describe the association of movements. And therefore the first 
chapter will briefly survey the way in which movements are 
combined associatively. 



MOVEMENT AND MENTAL IMAGERY 
CHAPTER I 

TYPES OF ASSOCIATION AMONG MOVEMENTS 

In animals highly enough organized to have a nervous 
system, we find as the essential feature of that system arrange- 
ments whereby a stimulus, that is, some form of physical en- 
ergy, may act upon the outer end of a nerve and start in it a 
process of nervous change, which is carried inward through the 
branch of a nerve cell or neurone affected, through the body of 
the nerve cell, outward along another long branch, then to the 
branch of another neurone across a point of contact called a 
'synapse,' through the cell body and the outgoing branch of this 
second neurone, across another point of contact or synapse, and 
through a third neurone down to a muscle, which the nervous 
process, reaching it through a chain of at least three neurones, 
causes to contract. Thus the animal performs a movement 
in response to a stimulus. A great number of such pathways 
exist in any of the higher animals, either ready at birth to make 
the animal move in a particular way when a certain force acts 
upon it (as when a young bird not yet hatched from the egg, 
under the stimulus of the mother's alarm cry, checks the piping 
noise it has been making), or developing in the course of the 
animal's growth, but developing out of its innate equipment 
and not learned by experience (as when the bird, when its 
nesting-time comes, builds a nest without being taught). 

So, because of innate pathways in the nervous system, an 
animal comes into the world ready to make, or to grow natur- 
ally to make, certain responses in the form of movements to 
the forces that act upon it from outside. These innate re- 
sponses are called * reflex movements,' and the nervous path- 
ways by which they are made are often called * reflex arcs.' But 



2 MOVEMENT AND MENTAL IMAGERY 

we cannot, of course, think of the nervous system as composed 
of an aggregation of disconnected reflex arcs. It is probable 
that every nerve cell with its branches, forming the unit called 
a 'neurone' has connections, directly or indirectly, with every 
other. This does not mean that the whole system is a physical 
continuity or network of nerve threads: rather, according to 
the best authorities, each cell w^th its branches is an independ- 
ent entity, the tips of whose fibres lie in contact with the tips 
of other neurone fibres. From any neurone in the nervous sys- 
tem, probably, it would be possible to pass, across many or few 
contact points or synapses, to any other. Whether the nervous 
process will actually pass from one neurone to another in a 
quite different part of the nervous system, however, will depend 
upon two conditions of the greatest importance. 

First, the points of contact between the fibres of different 
neurones — that is, the synapses — are apparently of such a 
nature that the nervous process can cross them in one direction 
but not in the opposite direction. If neurones A and B are in 
direct contact, and the nervous process can pass from A into 
B across the synapse, it will never be able to recross back to A. 
The synapse acts like a valve which allows passage in one direc- 
tion only. Thus, in a given reflex arc, a nervous process may 
start from a sense organ and travel to a muscle, but it can never 
travel back from the muscle to the sense organ. This law has 
been called the 'principle of the irreversibility of synapses.' 

Secondly, every synapse seems to offer a certain degree of 
resistance to the passage of the nervous process across it. Since 
every neurone is likely to be in contact with several others, the 
actual course of the nervous process out from a neurone will be 
over those synapses which offer the lowest degree of resistance. 
It will then be actually possible for the nervous process to 
travel from one neurone to another in a different part of the 
nervous system, only if the two are separated by synapses 
which allow the process to cross in that particular direction, 
and which offer resistances less than those of the synapses lead- 
ing in other directions. The nervous process could not travel 



ASSOCIATION AMONG MOVEMENTS 3 

from a muscle back to a sense organ because the synapses cannot 
be traversed in that direction. It could not pass even from a 
sense organ to a particular muscle if the resistances at the inter- 
vening synapses happened to be higher than those along a dif- 
ferent pathway. 

The amount of resistance at a synapse depends upon a num- 
ber of conditions. First, it is low along all innate reflex path- 
ways. Being born to make a movement means, probably, being 
born with low resistances at the synapses along the nervous 
pathway leading from the sense organ to the muscles. Thus 
resistance may be innately low along a reflex arc. It seems, in 
the second place, to be innately lower along certain reflex arcs 
than along others. That is, if two different reflex movements 
are simultaneously excited, one may have an innate advantage 
over another. This is especially true of movements having 
great significance for the welfare of the individual animal or the 
species. The water scorpion responds to the action of light by 
a turning movement that is of military precision, but if the in- 
sect is feeding, it does not react to light at all. The feeding 
reflex is master of the light reflex (52). A reflex that thus gains 
the victory because of specially low congenital resistance at its 
synapses is called a 'prepotent reflex.' The reaction of with- 
drawal from injury is a striking example of a prepotent reflex: 
it nearly always has the right of way. The resistance, thirdly, 
may be greatly heightened at certain synapses by being low- 
ered at others. That is, when the nervous process has a choice 
between two pathways which would lead to opposed, not 
merely to different, reactions, the probability that it will take 
one of them is not to be measured by subtracting the weaker 
resistances along one pathway from the stronger ones along the 
other. The fact that the nervous process starts along the line 
of the least resistance actually raises the resistances along the 
other line. While before one movement was actually begun the 
opposite one was to a certain extent possible, it is now less pos- 
sible by virtue of a certain amount of inhibition. The resist- 
ances at synapses, then, may be actually raised if a pathway 



4 MOVEMENT AND MENTAL BIAGERYi 

leading to an antagonistic movement is in action. Such antag- 
onistic movements, for instance, are those of extending and of 
flexing the fingers, or of singing a low and a high note. Fomthly, 
resistances at synapses are left, after the nervous process has 
passed across them, lower than they were before, so that, for a 
time at least, it is easier for the nervous process to take the same 
pathway again. And every time a nervous process transverses 
a synapse it reduces the resistance. 

All these statements are perfectly familiar to every student 
of psychology and of the physiology of the nervous system. 
Keeping them clearly in mind, we may pass on to survey very 
briefly the way in which reflex arcs are organized into systems. 
It is evident that in an animal whose structure is at all compli- 
cated, even a comparatively simple movement like the stretch- 
ing out of a paw involves the contraction of more than one 
muscle and the operation, therefore, of more than a simple 
reflex arc. Plainly, movements that an animal is born to make 
must require not only that resistances shall be low at the 
synapses along certain pathways in the nervous system, but 
that these pathways shall be organized into combinations, such 
that several pathways shall regularly be traversed together. 
Certain muscles must not contract unless certain other ones 
contract also : further, antagonistic muscles must be kept from 
contracting; that is, their contraction must be inhibited. A 
part of the inborn equipment for moving given to every animal 
consists in such groupings of pathways that the proper combi- 
nations can be brought about. The groupings, it is natural to 
assume, would be of two types: on the one hand, it would be 
arranged that a number of neurones leading from different 
points open to stimulation should converge into a * final com- 
mon path,' leading to the muscles, so that stimuli from these 
points should be able to combine in the production of the same 
movement. On the other hand, a neurone leading from a single 
point stimulated should have connections with neurones lead- 
ing to a number of different muscles, so that the movement 



ASSOCIATION AMONG MOVEMENTS 5 

made in response to a single stimulus may be a complex one, 
involving the contraction of one system of muscles and the re- 
laxation of others. For instance, a ray of light falhng on a single 
point of the retina should be able to bring about the rather com- 
plicated movements of raising or lowering the eyes until it falls 
on the fovea. At this point we may note that the organization 
of movements into systems does not seem to call for any direct 
connection between one neurone leading from a point of stim- 
ulation and another neurone leading from a point of stimula- 
tion; between what we may call, for short, one sensory neurone 
and another. Sherrington says (126, pages 140, 141), "In the 
central nervous system of vertebrates, afferent neurones A and 
B, in their convergence toward and impingement upon another 
neurone Z, towards which they conduct, do not make any lat- 
eral connection directly one with the other — at least, there 
seems no clear evidence that they do." The significance of this 
fact will appear later. 

But our concern is not primarily with the innate nervous 
organization of man or of animals. Bather, as psychologists we 
are interested in the changes which that organization under- 
goes in an individual's lifetime. The phenomena which we call 
* psychic,* which we can observe only each of us for himself, as 
contrasted with the facts of outward behavior which hundreds 
of persons can observe at the same time, seem to be connected 
not with innate behavior so much as with the acquisition of 
new ways of acting. The relation of consciousness to movement 
will be considered in the next chapter. Without further discus- 
sion of this point, let us turn to the ways in which new forms of 
movement are acquired by the organism. 

No simple new movement can ever be made. Just as we can 
get only the sensations we were born to get, so we can make only 
the simple movements we were born to make. Just as all the 
creations of imagination are only new combinations of old ele- 
ments, so all the complicated movements we acquire in a life- 
time — the skill of a mechanician, the fingering of a violinist — 
are new combinations of simple movements we were born to 



6 MOVEMENT AND MENTAL IMAGERY 

perform. We could learn to perform a new simple movement 
only if we could create a new muscle, and that no athletic 
training will do. The formation of new combinations, then, of 
movements that are themselves given to us by our inborn con- 
stitution, is what we have to study. 

Every simple movement that we are ever capable of perform- 
ing has some stimulus, or set of stimuli, which innately produces 
it. That is, not only are we born with a certain equipment of 
muscles, and of motor neurones which cause the contraction of 
these muscles, but these motor neurones are connected with 
sensory neurones, and the sensory neurones are connected with 
sense organs fitted for the reception of a certain definite stimu- 
lus that belongs to each reflex arc and will call forth each move- 
ment. The sole way in which experience can modify this state 
of affairs is that a stimulus may come to produce a movement 
which originally, innately, could be called forth only by a dif- 
ferent stimulus. Is the case, now, reversible? Does every 
stimulus by which our sense organs can be affected have a cer- 
tain definite movement that innately belongs to it? There 
must at least be a certain range of movements that it produces 
more naturally than any others. Every sensory neurone, cap- 
able of being acted on by an outside stimulus, is in contact with 
certain other neurones, and the resistances at the synapses be- 
tween it and them, whether great or slight, at least are not im- 
passably great, so that the movements to which these other 
neurones lead are innately susceptible of production by the 
stimulus in question. Every simple movement that we ever 
make we were born to make when a certain stimulus or set of 
stimuli acts upon us: to every stimulus for which we have a 
sense organ we were born to respond with a certain range of 
motor responses, if not with one single, definite, foreordained 
movement. 

A study of the processes of learning in man and in lower 
animals indicates that their essential feature consists in the 
acquisition by a stimulus. A, of the power to cause a movement 
whose original stimulus, B, occurred together, or nearly together. 



ASSOCIATION AMONG MOVEMENTS 7 

with A. Further, it appears that learning, thus understood, has 
two types. In one type, the stimulus A, in acquiring the power 
to produce the reaction that originally belonged to stimulus B, 
loses its own original reaction: it simply substitutes for the 
movement originally belonging to it the movement originally 
pertaining to stimulus B. In the other type, the single stimulus 
Ay while acquiring the power to produce B's motor response, 
preserves also its own original response. 

There are plenty of examples of the first type of learning. A 
whistle is blown before a dog is fed : the original reaction of an 
uneducated puppy to the sound might be that of cowering in 
fear; his original response to the actual sight of food would be 
running towards it. The sound of the whistle loses its fear 
response and assumes the response that belonged to the sight 
of food; the puppy runs to the feeding-place at the blast of the 
whistle. The sound of a musical tone has originally no power 
over the salivary reflex in a dog, the normal stimulus for such a 
reflex being the sight or smell of food, but Pawlow's (105) ex- 
periments show that when the tone has often been sounded 
before the animal was fed, the flow of saliva comes to be in- 
creased by the tone stimulus even in the absence of the food 
stimulus. The speed with which a response thus attaches itself 
to a new stimulus seems to depend on the vital importance of 
the response; that is, on its prepotency. Harm or great benefit 
to the organism are themselves stimuli which innately call forth 
certain movements, of withdrawal or approach. These move- 
ments, especially that of withdrawal, are, in general, prepotent; 
that is, the resistances at the synapses concerned are congeni- 
tally low, and a very slight degree of stimulus energy is enough 
to set them off. Learning to check or inhibit a movement that 
brings harm is simply a case where stimulus A, originally pro- 
ducing, let us say, a movement towards the flame, being fol- 
lowed by stimulus B, let us say, pain, whose natural and innate 
response is that of withdrawal, quickly, indeed immediately, 
drops its own reaction and assumes the withdrawing response 
proper to pain. The next time, the sight of the flame produces 



8 MOVEMENT AND MENTAL BIAGERY 

the withdrawing response at once: there is no need to wait for 
the pain. Schaefer (120) found that the green frog learned to 
avoid disagreeable caterpillars in two or three trials : the sight 
of the caterpillar was a stimulus that had cast aside its original 
motor response of seizing and acquired the new response of 
avoiding. 

The second type of learning is important where new combi- 
nations of movements are to be formed. In the type just de- 
scribed, the movements themselves are old, not only as regards 
their elementary components, but even in their combinations : 
the only new thing is their being made in response to the par- 
ticular stimulus used. It is nothing new for a dog to run; not 
only the individual component muscular contractions, but the 
whole system of them, is innate. What is new is that he should 
run towards the sound of a whistle. But in the second type of 
learning, where stimulus A comes to produce the reaction of B 
in addition to its own congenital response, evidently a new com- 
pound movement is acquired. Now in the formation of a new 
combination of movements the essential thing is that there 
shall be no dropping out, in the learning process, of any move- 
ment that really belongs in the system. The first type of learn- 
ing is characterized by the elimination of a movement or move- 
ments. The reaction of running away from the whistle needs 
to be dropped out and that of running towards it substituted. 
No combination of the two responses is the proper result. On 
the other hand, a good example of learning of the second type, 
the formation of a new movement combination, is the getting 
by heart of a series of nonsense syllables, so that the articula- 
tory movements involved in pronouncing them shall be made 
smoothly and rapidly with no looking at the printed or written 
list on the reciter's part. Evidently in such a case it is far from 
desirable that any of the movements shall be eliminated. All 
of the syllables need to be pronounced: what is aimed at is not 
a short cut from the first to the last syllable in the series. 

The most natural way of conceiving the arrangement by 
which such a system of mutually dependent movements is se- 



ASSOCIATION AMONG MOVEMENTS 9 

cured is to suppose that a part, at least, of the stiniulus for 
every movement in the combination is furnished by the actual 
performance of the other movements. The contraction of a 
muscle does, as a matter of fact, stimulate certain * sensory' 
neurones; that is, neurones whose synapses allow the passage of 
the nervous process away from rather than towards the outside 
of the body; towards, rather than away from, the spinal cord 
and the brain. Muscular contraction may itself stimulate re- 
flex arcs, as may light, heat, touch or sound: the stimulus for 
a movement may thus easily be the actual performance of an- 
other movement. The convenient term * proprioceptive re- 
flexes' has been used to mean reflexes whose stimulus is the 
process of muscular contraction itseK: reflexes whose stimu- 
lus is some force outside the body are called * exteroceptive.' 
Now, if it is an essential feature of our second type of learn- 
ing that all the movements must be preserved, a very good 
way of making sure that certain movements in the set should 
not occur without the others would be to make the necessary 
stimulus for their occurrence lie in the performance of the others. 
If the necessary stimulus for pronouncing the last syllable of a 
series were the muscular contractions produced in pronouncing 
the next to the last syllable, then the proper sequence of move- 
ments would be insured. When a series of syllables is learned by 
heart, or a series of finger movements in playing the piano, we 
get evidence that the movements have reached this degree of 
organization, for we can usually recall a given movement in the 
series only by running the series through. 

In this type of learning process, movements often occur 
which do get eliminated. A baby learning to repeat a nursery 
rhyme pronounces it month by month more correctly, dropping 
out the unsuccessful articulatory movements and supplanting 
them with others. A rat is taught to run through a complicated 
labyrinth to the food at the centre. Undoubtedly a system of 
movements is formed in such a case wherein each turning 
movement forms a part of the stimulus for the next. But in 
learning the maze path the wrong turnings get eliminated, 



10 MOVEMENT AND MENTAL IMAGERY 

dropped out. Thus both types of learning are found side by 
side: the 'wrong' movements are ehminated and the * right* 
ones organized into an interdependent system. We have seen 
that when one movement is dropped out in favor of another 
one, the latter is usually a prepotent movement; that is, one 
which the organism is congenitally more ready to make, whose 
synaptic resistances are congenitally low. The successful or 
right movements must then be prepotent over the wrong ones. 
If a movement of approach leads to actual harm, that of with- 
drawal will substitute itself, being a prepotent reflex par excel- 
lence. Thus, many unsuccessful movements will be dropped out 
because they become connected with a withdrawing tendency 
that is antagonistic and inhibitory to them. We need not, how- 
ever, discuss further the unsolved problem as to just how bene- 
fit and harm, success and failure, operate to 'stamp in' and 
'stamp out' various movements connected with them. Our 
concern is simply to make clear the difference between the type 
of learning which involves the elimination of movements and 
that which involves their preservation and organization into 
systems. 

Let us use the term movement system to indicate a combina- 
tion of movements so linked together that the stimulus furnished by 
the actual performance of certain movements is required to bring 
about other movements, A useful term for a stimulus furnished 
by the performance of a movement is ' kinsesthetic stimulus.' 
There are certain classes into which movement systems natu- 
rally fall. 

In the first place, not all muscular contractions produce what 
we should ordinarily call movements. Holding up one's head, 
in its ordinary erect position, for several hours is not what one 
thinks of as a movement. Yet it involves the contraction of 
certain muscles: it is not merely an effect of gravity such as 
that which keeps a snow-man's head on his shoulders. The 
maintenance of bodily postures, as distinguished from the 
movements by which these postures are reached, is evidently 
due to the continued contraction of certain muscles and the 



ASSOCIATION AMONG MOVEMENTS 11 

relaxation of certain others. We may designate movement 
systems which involve prolonged states of contraction and 
relaxation of muscles as * static movement systems'; those 
which involve actual translations in space, movements as we 
commonly understand the term, will be termed * phasic move- 
ment systems.' 

Secondly, it is clear that an important difference in phasic 
systems relates to whether the movements are successive or 
simultaneous. In static systems, on the other hand, evidently 
the muscular contractions take place simultaneously: if one 
were to succeed another, change of position would occur, in- 
stead of that steady maintenance of a condition which is in- 
volved in the notion of a static system. But the carrying out 
of a phasic system may require the simultaneous contraction 
of several muscles, or their successive contraction, or both. 
We may therefore conveniently divide phasic movement sys- 
tems into 'simultaneous' and 'successive' systems. 

Plainly, the main difference between simultaneous and suc- 
cessive systems lies in the degree of interdependence that exists 
among the various movements which form the system. Such 
movements as those of skating or riding a bicycle require the 
contraction of a number of muscles in different parts of the 
body at the same time. To secure the making of these move- 
ments together, when the movements are thoroughly learned, 
it is most natural to conceive that each component movement 
furnishes an essential part of the stimulus for all the other 
components : it would be useless or even dangerous for any one 
of the movements to occur without the rest. On the other 
hand, take again the reciting of a series of nonsense syllables as 
an example of a successive system. The movements of pro- 
nouncing the second syllable have as a part or the whole of their 
stimulus the movements of pronouncing the first syllable, but 
of course the pronouncing of the second syllable does not stim- 
ulate that of the first : the connection is not mutual. In a simul- 
taneous phasic system, then, as in a static system, each muscu- 
lar contraction furnishes part of the stimulus for every other 



12 MOVEMENT AND MENTAL IMAGERY 

muscular contraction. But in a successive phasic system the 
process is chain-Hke : the performance of a particular muscular 
contraction furnishes the stimulus for one other only, which 
accordingly follows it. 

Let us now inquire into the possibility of various types of 
successive phasic systems. Does there exist a type (a) where 
the movements are linked in such an order that they cannot 
easily be reversed? Is there a type (b) where the order of the 
movements within the system is wholly indeterminate .? Does 
a type (c) exist in which the order of the movements is fixed but 
reversible? 

Examples of type a, irreversible systems, are easy to find. 
The pronunciation of a word of more than one syllable, say, the 
word * syllable' itself, involves a system of movements that 
cannot be reversed. The writing of a word with pen or on the 
typewriter involves also a set of movements whose order is ab- 
solutely determined: the performance of a particular move- 
ment, required for writing the first letter of the word, gives the 
stimulus for the performance of only one other movement in 
the system, that required for writing the second letter. We 
have already used the recitation of a series of nonsense syllables 
as an illustration: it is evidently a case of an irreversible system 
of movements. 

Is there, now, such a thing as a successive movement sys- 
tem in which the order of succession of the movements is not 
determined (type 6)? Such systems, if they exist, might be 
called systems of indeterminate order. Given the performance 
of any one movement of such a system, it may furnish the 
stimulus, if the order be wholly indeterminate, for any other 
movement in the system; this in turn may produce any other 
movement; and so on. Would not such a system resolve itseK 
into a simultaneous system? Would not, that is, the first 
movement to be performed excite simultaneously all the others, 
since it is by hypothesis capable of exciting them all? 

There seems no reason why a system of indeterminate order 
should not always be a simultaneous system, provided that its 



ASSOCIATION AMONG MOVEMENTS 13 

various movements were compatible, and could actually be 
performed at the same time. But suppose they are incom- 
patible. Let us take, for example, a musical chord. One listens 
to it, and analyzes it, with a tendency to sing the various notes. 
It is impossible to sing more than one note at a time. Our analy- 
sis, then, must pass from one note of the chord to another, but 
there is no determinate order of succession in which we do so. 
The movements cannot be simultaneous, for they are incom- 
patible, but their order may be varied in all possible ways. 

But this possibility of varying the order, in the case of the 
musical chord, is due to the fact that there are external stimuli, 
the tones, acting upon us, simultaneously and continuously, so 
that no matter which one is attended to first, the others will 
patiently wait their turn. In other words, the movements in- 
volved in analyzing the chord do not form a true movement 
system at all. For in a movement system no outside stimulus is 
necessary except for the initial movement: the others have as 
their sufficient stimulus the kinsesthetic, proprioceptive proc- 
esses started by the actual performance of other movements in 
the system. Clearly, then, it is not possible for a true move- 
ment system to exist which is at the same time successive and 
indeterminate in the order of its succession. For a set of move- 
ments to present this character there must be a set of simulta- 
neous and fairly persistent stimuli: now, if these stimuli were 
themselves produced by movements, as they must be in a true 
movement system, then the system would obviously be simul- 
taneous and not successive. 

Thirdly, do there exist successive movement systems whose 
movements exhibit an order that is determinate but reversible 
(type c) ? In such a system, if the various movements that com- 
prise it be represented by the letters a, 6, c, d, and e, movement 
a may furnish the stimulus for the performance of one move- 
ment only, namely, b; 6, however, may give the stimulus for 
either movement a or movement c; that is, the series, if it 
starts at 6, may proceed either forward to c or back to a. If c is 
the first movement to be performed, it may furnish the stimu- 



14 MOVEMENT AND MENTAL BIAGERY 

lus either for d, in the forward direction, or for h in the back- 
ward direction. In like manner, d may call forth either c or e; 
e, of course, unless the system is to end, can excite only d, in the 
backward direction. Thus, each movement in the system, ex- 
cept two, a and e, has two possibilities of exciting other move- 
ments: a and e, on the other hand, have only one. Evidently 
the two movements whose possibilities of stimulation are thus 
restricted are not necessarily the jfirst and last in time. A re- 
versible series may begin anywhere. The first movement, in 
point of time, may be movement h; the second may be a; then 
the series may reverse itself and the third movement be h again, 
the fourth c, the fifth d, the sixth ^, and the seventh and last d 
once more. Neither a nor e would be either the first or the last 
movement in point of time, in such a case. Yet nevertheless a 
and e occupy a peculiar position in the system, for each of 
them has only one possibility of exciting another movement, 
while all the other movements in the system have two possibili- 
ties. It is quite evident that the kind of sequence thus involved 
is what we mean by a spatial rather than a temporal sequence. 
In a linear spatial series of points it is possible to move in two 
directions from any point except the points at the extremities of 
the line; from these one can move in one direction only. On a 
surface it is possible to move in any direction from any point 
except points at the boundary lines of the sm-face, and from 
these the possibilities of movement are much less than they are 
from other points. Taking the retina as an example of a sur- 
face bounded by a curved line, the possibilities of moving from 
any point within the circumference are decidedly greater than 
the possibilities of moving from a point on the circumference. 
Do eye movements form an irreversible movement series, and 
does this constitute the spatial character of visual experience? 
Clearly nothing like the type of process we have described as 
a reversible movement series occurs in the case of eye move- 
ments. The eyes are moved by antagonistic pairs of muscles: 
one muscle by its contraction moves the eye to the right, an- 
other to the left, a pair, contracting simultaneously, raise it. 



ASSOCIATION AMONG MOVEMENTS 15 

and another pair lower it. The extent of an eye movement in 
any direction is Hmited by the power of the proper muscle or 
pair of muscles to contract. Any eye movement short of the ex- 
treme movements in any direction is produced by a contraction 
of precisely the same muscles as are involved in an extreme 
movement, only of less energy. If, as is obviously true, the eye 
cannot move so as to fixate the end of a line without sweeping 
over the points between, this means, not that there is a certain 
fixed succession of distinct movements, but that a single move- 
ment cannot reach its maximum energy without passing 
through the intervening degrees. These increasing degrees of 
energy, however, are not separate movements, and do not con- 
stitute in any sense a movement system. Nor are the motor 
processes by which the contraction of the muscle moving the 
eye is checked at different points capable of forming a move- 
ment system : they are always the same checking or inhibiting 
process, consisting in the contraction of the same antagonistic 
muscles, whether the checking occurs after a movement of 
brief or of longer duration. No eye movements, so far as one 
can judge, combine according to the type of a reversible move- 
ment system. 

Eye movements, however, as well as the movements of cer- 
tain other pairs of antagonistic muscles, may form the basis of 
successive movement systems that serve the purpose of revers- 
ible systems. These are series of movements, each series irre- 
versible in order, but the order being opposite in each. Take a 
very simple example. We see a blue spot to the left of our field 
of vision, a red spot in the middle, a green spot on the right. As 
our eyes move from one side of the field to the other, we get the 
sensations in the order, blue, red, green : we can then move our 
eyes back and get the order: green, red, blue; or we can start 
with red and get the order red, green, red, blue; but we cannot 
get from green to blue without passing through red. Now, sup- 
pose that we name the colors as we look at them. The articu- 
latory movements will form two series: blue, red, green, and 
green, red, blue. Each of these is a fixed and irreversible series, 



16 MOVEMENT AND MENTAL IMAGERY 

but the two may be established with equal firmness and form 
equally strong systems. Such a possibility, that a set of stimuli 
shall establish with equal strength movement systems in which 
the sequence of movements is opposite in direction, is furnished 
us only by a spatial series of sensations: may we not say that 
furnishing this possibility constitutes a spatial series of sensa- 
tions? 

To sum up, then: the successive movement system is typi- 
cally and regularly a system in which the order is determined 
and irreversible. A system of movements with indeterminate 
order is not a successive movement system at all, but a simul- 
taneous system : a set of movements with reversible order, if the 
movements are really different movements and not merely dif- 
ferent durations of the same movement, resolves itself into two 
successive movement systems, each with a determined and irre- 
versible order of succession, the orders being opposite in the 
two systems. 

Finally, there is still another way in which movements may 
be combined. Instead of forming a system, they may form 
what we shall call * sets.' A set of movements comprises a num- 
ber of movements whose only relation to each other is that they 
are all associated with one common movement. Thus, the vari- 
ous possible means of realizing a certain desire may be entirely 
different from and independent of each other, but they are all 
alike capable of being excited by the movements which consti- 
tute the desire. The various words which indicate one of two 
opposed qualities, such as *hard,' 'high,' * smooth,' have noth- 
ing in common with one another; but they are all alike associ- 
ated with the word ' opposite.' We shall find several instances 
of the functioning of such sets of movements. 



CHAPTER II 

MOVEMENT AND CONSCIOUSNESS 

What do we mean by 'consciousness'? Every one knows 
what is meant when it is said that a man is unconscious. He is 
neither awake, aware of the sights and sounds of the outer world, 
nor dreaming, aware of images that are the product of his own 
fancy. Consciousness is that which is present when we are 
either awake or dreaming, and which is absent when we are 
dreamlessly asleep. That we can define it in no more direct way 
than this need not disturb us; even the term * behavior' must 
include in its definition terms that are no more adequately de- 
finable than consciousness is. Behavior involves movement, 
and movement is change of position in space; but when we try 
to define space, we find ourselves in just the same kind of situ- 
ation as when we try to define consciousness : every one knows 
what we mean, but since both space and consciousness are ulti- 
mate notions, not to be classed with anything else, we cannot 
give them definition, for to define is to classify. 

Consciousness, then, we shall take as meaning that which is 
present when we are awake or dreaming, and absent when we 
are dreamlessly asleep. The question which we are to discuss 
in this chapter is : what is the relation of consciousness to move- 
ment? Is there any such thing as consciousness that has no 
relation to bodily movement? 

Much of our consciousness is directly related to bodily 
movement. The greater number of the movements which a 
person makes during the day are recognized by others as the 
expression of what is going on in his consciousness. If he 
frowns or laughs; if he speaks, eats, sits down, walks in a cer- 
tain direction, we take it all as the outward sign of certain con- 
scious experiences on his part; of emotions, ideas, desires. Yet, 
on the one hand, we realize that some of his movements have 



18 MOVEMENT AND MENTAL EMAGERY 

no accompaniment in his consciousness, and, on the other hand, 
we know, because he later tells us so, that at times when we can 
see no movement in him he is yet conscious of thoughts and 
mental images. On the one hand, we know that his heart mus- 
cle is in constant motion without his being conscious of the 
fact: here is movement without consciousness. On the other 
hand, we see him lying with eyes closed and muscles all relaxed, 
yet, when later accused of having been unconscious, he tells us 
of the train of thought that was passing through his mind : here 
is consciousness without visible movement. Shall we, then, say 
that there are three orders of phenomena here: movement 
without consciousness, movement with consciousness, and con- 
sciousness without movement? Or shall we try to unify these 
three orders, and declare that the apparently unconscious 
movement is really conscious, and the apparently non-motor 
consciousness is really motor, so that consciousness and move- 
ment always accompany each other? Or shall we adopt a mid- 
dle ground, and say that movement is broader than conscious- 
ness; that while there may be unconscious movement, there can 
be no consciousness without a motor basis? Still another mid- 
dle position is evidently theoretically possible, namely, to 
assert that consciousness is broader than movement, and that 
while all movement is conscious, there is such a thing as con- 
sciousness unrelated to movement. 

This last possibility, however, suggests that we examine the 
kind of evidence which leads us to conclude that consciousness 
is present in a given person at a given time, and to compare it 
with the kind of evidence that leads us to conclude the presence 
of movement. Of the presence or absence of consciousness in- 
trospection is the final witness. And the testimony of introspec- 
tion on this point cannot be gainsaid. It is true that if I tell you 
from introspection, on waking, that I have not been conscious 
of what has been happening about me, it may be argued that I 
have forgotten my previous state of consciousness in the shock 
of waking. But if it can be demonstrated that a certain move- 
ment is occurring in my body, and if I assure you that I am 



MOVEMENT AND CONSCIOUSNESS 19 

unconscious of that movement, there is no possible ground on 
which any one can urge that I am mistaken. When a bright 
Hght is brought near, the pupils of my eyes contract. An ob- 
server informs me that they do so, but I do not feel the move- 
ment. There certainly are, then, unconscious movements. 

The kind of evidence on which we may assert the non-exist- 
ence of movement is different. It is external observation, and 
its accuracy depends on the means of observation that are at 
hand. I look at a person lying apparently asleep. I see the 
rise and fall of his chest, and the throbbing of his pulse; can I, 
because I see no other evidence of movement in him, conclude 
that these are the only motor processes which are taking place? 
No; I know that there are other motor processes going on which 
are withdrawn from my observation, such as those connected 
with digestion : these, however, belong to the class of movements 
normally unaccompanied by consciousness. But suppose the 
man is really awake and thinking deeply : I cannot possibly be 
sure that there is not connected with every one of his thought 
processes a process of movement, which I am unable to observe 
simply because I lack the material means to observe and record 
it. The man himself can in many cases discover such motor 
processes by introspection; can detect that as he thinks, slight 
movements of his vocal organs occur, he says things to himself, 
there occur slight twitchings of his fingers, movements of his 
eyes, variations in his breathing rate. It would never be safe 
to assert positively, then, that consciousness occurs without 
any accompaniment of bodily movement, for movements may 
be of a nature such as to escape our present means of observa- 
tion. 

There are certainly movements unaccompanied by conscious- 
ness. On the other hand (a) all consciousness may be accom- 
panied by bodily movement, or (6) there may be some conscious 
processes that really have no motor accompaniment. The evi- 
dence from observation is insuflScient to decide between these 
two possibilities. 

It is the aim of this book to assume one of the alternatives 



20 MOVEMENT AND MENTAL IMAGERY 

which we have just stated, and to see whether it can suffice as a 
working hypothesis. Can we construct a working theory out of 
the assumption that all consciousness is related to movement? 

Starting with the assumption that consciousness is always 
related to bodily movements, and holding on introspective 
evidence that some bodily movements are unconscious, we may 
ask whether the movements on which consciousness depends 
are free, unhampered movements, or checked, difficult movements ? 
This is a problem which has not yet been satisfactorily solved 
even by psychological theory. Let us see just what the diffi- 
culty is. 

On the one hand, introspection suggests that the more 
smoothly and easily a movement occurs, the less consciousness 
accompanies it. The process of habit formation is the convinc- 
ing instance of this. A beginner at riding the bicycle makes the 
movements of balancing himself with anxious attention and 
care; later they occur smoothly, accurately, and unconsciously. 
In current physiological theory the ease with which a movement 
is performed is held to be due to the low resistance offered at 
the synapses or meeting-points of neurones wliich the nervous 
process has to traverse: hence it has been suggested that con- 
sciousness accompanies a high degree of synaptic resistance, 
unconsciousness a low degree. As Montague (86) has put it: 
" Perceptions are presumed to arise synchronously with the 
redirection in the central nervous system of afferent currents 
into efferent channels. When this process of redirection is pro- 
longed by reason of the many conflicts with the cerebral associ- 
ation currents, then the consciousness is prolonged, keen, and 
complex. When, on the other hand, by reason either of innate 
adjustments or of long practice, the journey through the central 
labyrinth is quick, smooth, and direct, then the consciousness, if 
present at all, is simple, faint, and brief" (page 128). 

But, on the other hand, a difficulty arises in the way of 
asserting that consciousness is directly proportional to the 
amount of resistance at the synapses. And this difficulty is 
concerned with attention. One would certainly say that atten- 



MOVEMENT AND CONSCIOUSNESS 21 

tion and consciousness cannot be governed by opposite laws. 
That which we attend to is that of which we are most conscious. 
Attention would seem to be the highest degree of consciousness. 
Now, attention to one object involves diminished conscious- 
ness of other objects. And apparently the motor responses 
which we should otherwise make to these other objects are often 
suppressed when attention is directed elsewhere. If we had 
been attending when the telephone bell rang, we should have 
risen to answer it, but this well-established response to the bell 
was suppressed because our attention was fixed on something 
we were reading. Such a suppression must have involved a 
very high degree of resistance along the getting-up-and-going- 
to-the-telephone pathways; yet this high resistance did not 
mean heightened consciousness of the sound of the bell. The 
exact contrary was the case. The recognition that complete 
checking of a motor response often occurs when the stimulus 
to that response is not attended to led Miinsterberg (95) to for- 
mulate the statement that the vividness of a conscious process 
is greater, the freer the pathway to motor discharge is. This 
statement seems to be, and as a matter of fact is, a direct con- 
tradiction of the statement made above, that free motor dis- 
charge means lessened consciousness. His critics were not slow 
in quoting against Munsterberg's theory of free motor discharge 
as conditioning vivid consciousness, the facts of habit formation. 
His reply to the objection was to declare that habits are based 
on connections in the nervous system below the level of the 
brain cortex, and are therefore not subject to the conditions 
that prevail in the cortex. He said: *Tt is merely a specious 
argument against the Action Theory to urge that impressions 
become less vivid the more readily they pass over into move- 
ment, and are apparently wholly inhibited if the movement 
takes place entirely without resistance. If we were really forced 
to the anatomical view that mechanized reactions still pass 
through cortical centres, the Action Theory would be indeed 
untenable. . . . Such an anatomical interpretation is, however, 
clearly indefensible. The mechanization of the passage from 



22 MOVEMENT AND MENTAL IMAGERY 

centripetal to centrifugal excitation means the formation of 
subcortical connections, by means of which the disturbance 
coming from the periphery is conducted to an outgoing path- 
way before it reaches the psychophysical cortical apparatus at 
all. ... As long as the stimulus really has to go to the cortex, 
it never, however frequently rei>eated, becomes unconscious" 
(page 541). This answer treats the diflSculty in too cavalier a 
fashion. One naturally wonders at just what point in the for- 
mation of a habit the transference from cortical to subcortical 
connections, and the consequent complete reversal of the rela- 
tions between the learning process and consciousness, occurs. 
Let us suppose that a series of movements has become mechan- 
ized, and has thus by hypothesis passed into the control of sub- 
cortical centres. Yet, as a matter of fact, no habit is ever so 
perfectly acquired that if an obstacle occurs in its free per- 
formance, attention is not drawn to it. Thereupon, according 
to the Action Theory of Munsterberg, cortical pathways are 
brought into play, and as soon as this occurs, the interrupted 
movement should cease to be attended to because it is inter- 
rupted. The very cause that shifted its performance from sub- 
cortical to cortical levels, and thus made attention possible, 
prevents it from getting attended to. 

The difficulty, then, remains that one body of facts seems to 
suggest that consciousness is correlated with delayed and ob- 
structed movement, while another body of facts suggests that 
stimuli which are not represented in consciousness often have 
their motor responses entirely suppressed. 

It is possible, I think, to find a real solution of this difficulty, 
but in order to reach it, we shall have to make a careful survey 
of the ways in which bodily movements are interfered with or 
suppressed. 

There are two ways in which muscles are related as re- 
gards their joint action. First, there are non-antagonistic 
muscles. These can be contracted at the same time without 
mutual interference. Their contraction may result from one 
and the same stimulus, and they are then said to be identically 



MOVEMENT AND CONSCIOUSNESS 23 

innervated : several muscles that have to cooperate in the per- 
formance of a change in the position of a Hmb are innervated 
in this way. Or their contraction may result from different 
stimuli : the movements of walking and talking, for example, 
may go on quite well together with no interference. 

Secondly, we have antagonistic muscles. These are muscles 
each of which would move a limb in a direction opposite to 
that in which the other muscle would move the limb. Thus 
the muscle that lifts the forearm is antagonistic to that which 
lowers it. The contractions of these muscles are antagonistic 
movements, and the relation between antagonistic muscles is 
one of * double reciprocal innervation.* That is, when one of 
them is excited, the other is proportionately inhibited. Yet it 
would be a mistake to suppose that the two muscles of an an- 
tagonistic pair can never be simultaneously contracted. They 
can be, under two conditions. On the one hand, they may be 
simultaneously contracted as the result of the action of equal 
stimuli, if the amount by which each stimulus excites one mus- 
cle is greater than the amount by which it inhibits the other 
muscle. There will then be left over for each muscle a surplus 
of excitation, equal in amount to the excitation of the other 
muscle, and the two antagonists will be simultaneously and 
equally contracted. Of course, no actual movement of the part 
of the body thus acted upon can result; what results is a fixed 
posture or attitude. A fixed position of the eyes may result 
from the simultaneous contraction of antagonistic eye muscles; 
or a fixed position of the forearm bent at an angle of forty-five 
degrees may result from the equal contraction of the muscles 
which raise and lower it. On the other hand, if one of the an- 
tagonists is more strongly excited than the other, even then the 
other may contract and exert a certain inhibitory influence on 
the contraction of the more strongly excited antagonist. The 
effect of this is movement in the direction of the stronger com- 
ponent, but movement that is slow and controlled, instead of 
being free and rapid. The arm may be slowly raised, for in- 
stance, under this combined influence of antagonistic muscles: 



24 MOVEMENT AND MENTAL IMAGERY 

as Sherrington says, there is algebraic summation of the exci- 
tations and inhibitions (127). 

Now while it is perfectly possible for antagonistic muscles 
to contract at the same time, as we have just seen, it is clearly 
impossible for a limb, or any part of the body, to be actually 
moved in opposite directions at the same time. It is not possible 
for the arm actually to move up and down at the same time; 
or for the hand to draw a circle from left to right and from right 
to left at the same time, or for the muscles of articulation to 
pronounce p and o at the same time, since the former involves 
closing and the latter opening the lips. The reason why such 
movements cannot be simultaneously performed is not merely 
because they involve antagonistic muscles, but because, if a 
member could be moved in two opposite directions at the same 
time, the muscle moving it in one direction would have to be at 
once more strongly and less strongly innervated than its an- 
tagonist : the thing is logically an impossibility. We shall use 
the term ' incompatible movements ' to designate movements 
that cannot be performed together. 

Let us now suppose that two stimuli, which we will call S 
and *S', simultaneously act upon the body, and that the motor 
responses which belong to these stimuli are antagonistic. S will 
then excite the response M by an amount which we will call 
eMy and will inhibit M' by an amount which we will call iM\ 
In like manner, S' will excite 3f ' by an amount which we will 
call eM\ and inhibit M by an amount which we will call iM. 
The amount of actual excitation which M undergoes will clearly 
be equal to the difference eM — iM, and the amount which if' 
undergoes will be equal to the difference eM' — iM'; that is, 
each centre will have the amount of excitation it receives from 
its own stimulus diminished by the amount of inhibition it re- 
ceives from the antagonistic stimulus. (1) Now, suppose that 
these residual innervations of M and M' are equal. Both motor 
discharges will occur, weakly or strongly according to the 
actual amount of excitation left after deducting the inhibi- 
tions: but no actual movement will take place. There will be 



MOVEMENT AND CONSCIOUSNESS 25 

an attitude, involving balanced contraction of the two antagon- 
ists. (2) Suppose, on the other hand, that one excitation, that 
in My is, after deducting the inhibitory effect of *S', stronger 
than the excitation in M' left after deducting the inhibitory- 
effect of *S. In this case there will also be contraction, weak or 
strong, of both antagonists, but as a result of the greater 
strength of excitation in M there will also be actual movement, 
slight or strong, in the direction in which M moves the limb or 
other part of the body concerned. The chief difference in the 
actual nervous processes involved between case (1) and case 
(2) will be that different sensory excitations will be produced by 
the resulting attitude in one case and actual translation of 
position of the limb in the other. If these kinsesthetic excita- 
tions are accompanied by consciousness, we should say that 
* it feels different ' to maintain a fixed position and actually to 
move a part of the body through space. 

Now may the truth with regard to the opposed positions, 
that consciousness accompanies obstructed motor discharge 
and that it accompanies free motor discharge, not lie between 
them : namely, in the statement that consciousness accompanies 
a certain ratio of excitation to inhibition in a motor discharge, 
and that if the amount of excitation either sinks below a cer- 
tain minimum or rises above a certain maximum, conscious- 
ness is lessened .f^ This idea will be more fully expressed in the 
next chapter. It is not necessary to speculate further as to the 
exact nature of the event that constitutes consciousness. One 
may hold that consciousness, while it accompanies a certain 
ratio of excitation to inhibition, is itself a phenomenon of 
wholly different nature from nervous phenomena; or one may 
adopt some such suggestion as that of Montague (86), who 
holds that consciousness is identical with the potential energy 
into which a portion of the kinetic energy of the stimulus is 
transformed when there is a check in the motor discharge. One 
would have in the latter case to account for the fact that a 
motor excitation that is too completely suppressed apparently 
gives rise to no consciousness; but it might be argued that a 



26 MOVEMENT AND MENTAL IMAGERY 

consciousness is occasioned which is so far spUt off and dis- 
sociated from the rest of consciousness as not to be introspec- 
tively discoverable. However, the consciousness in which we 
are interested is that which introspection can reach, and con- 
sciousness in this generally understood sense appears to accom- 
pany a motor discharge which is at once excited and inhibited, 
the amount of excitation being neither too slight nor too great. 
The other parts of the hypothesis which will be developed in 
the next two chapters are as follows. The kind of conscious- 
ness which we call an * image* or 'centrally excited sensation,* 
such as a remembered or imagined sensation, also depends on 
the simultaneous excitation and inhibition of a motor pathway. 
The * association of ideas' depends on the fact that when the 
full motor response to a stimulus is prevented from occurring, 
a weakened type of response may take place which we shall 
call ' tentative movement.' These movements are actual slight 
contractions of the muscles which the larger movements would 
involve; they are sometimes discoverable by introspection and 
sometimes not; sometimes observable by external means and 
sometimes not. They may very likely depend on a special sys- 
tem .of motor neurones. They enter into movement systems, 
both successive and simultaneous, just as do the larger move- 
ments corresponding to them. 



CHAPTER III 

MOVEMENT AND THE IMAGE OR CENTRALLY 
EXCITED SENSATION 

In the last chapter we found reason for thinking that a 
stimulus produces an effect on consciousness when it initiates 
a motor response which is partly checked in its execution by a 
process of inhibition, through the influence of an antagonistic 
motor response. The conscious process that is thus directly 
occasioned by the action of an outside stimulus is called a 
* sensation,' and may be further distinguished as a 'peripherally 
excited sensation,' to denote the difference between it and a 
centrally excited sensation or image. For we can get, as con- 
scious experiences, sensations not only from outside stimuli, 
but by the processes which are commonly known as 'memory* 
and 'imagination.' Not only can I see red when red light is 
acting on my eyes, but I can call up a mental image of red, 
and even, with fair accuracy, images of a whole series of dif- 
ferent shades and tones of red. I can not only hear the tones of 
a violin playing the "Prize Song" from the Meistersinger when 
the violinist is actually before me (or the phonograph is actually 
running), but I can sit here in my study, with no actual sound 
stimuli acting on my ears save the voices of the children across 
the street, and hear the tones of the violin through the entire 
air. The very important question now confronts us as to 
whether these images or centrally excited sensations are each 
one of them dependent on an incipient motor process, as the 
corresponding sensations would be if outside stimuli were act- 
ing. 

A fact clear to any observation is that there often intervenes, 
between the giving of a stimulus and the making of a move- 
ment that an outsider can see, a long interval. A man is sitting 
in his business office. To him there enters an acquaintance and 



28 MOVEMENT AND MENTAL IMAGERY 

asks him to write a check for one hundred dollars. The man of 
business says nothing, and makes no visible movement for a 
considerable interval of time. His friend knows very well, how- 
ever, that the request has ^been heard and is being pondered, 
and waits patiently. At the end of a certain period, the business 
man draws his check-book and his pen to him and carries out 
the request. He responds to the original stimulus by making 
the same movements which he might appropriately have made 
to it at once; but during the interval between stimulus and 
response, he will report from introspection, a train of proc- 
esses has passed through his consciousness which had no out- 
side stimulus; which belonged to the class of centrally rather 
than peripherally initiated conscious processes. He may have 
heard in memory the words of another friend urging the claims 
of the cause to which he is asked to give; he may have had a 
mental picture of some scene from his past. 

Now, it would be quite possible to hold (a) that while these 
conscious processes are, taken all together, the whole series of 
them, caused by the delay in responding to the original outside 
stimulus, and thus conditioned by the initiation of the final 
motor response, the several and individual centrally excited 
processes, images, or thoughts, that filled up the interval were 
not, each of them, dependent on an initiated motor response of 
its own. On the other hand, I think a very good case can be 
made out for the hypothesis (6) that each of these centrally 
excited processes, thoughts, or images, is dependent on its own 
special motor response. If the first view (a) is maintained, we 
should suppose that the energy of the stimulus S, not finding 
full discharge into the motor pathways of the response, passes 
directly through a series of sensory centres and finally, by this 
indirect route, finds its way back into the motor outlet which 
by the direct route was not fully open. As the nervous process 
traverses each of the series of sensory centres, there occurs, it 
would be held, a centrally excited conscious process in quality 
like the sensation which the centre in question would mediate if 
it were excited by an external stimulus. To take a simple ex- 



MOVEMENT AND THE IMAGE 29 

ample: the words, *I promised my wife to give this money,* 
may pass through the mind of the man who sits silently ponder- 
ing between the request for the money and the writing of the 
check. According to hypothesis (a), the energy of the stimulus 
(the request for the money) passes directly through a series of 
auditory sensory centres, and the accompaniment in conscious- 
ness is the mental hearing of the words in question. The im- 
plication of this view is that every sensory centre may have its 
functioning accompanied by consciousness under two wholly 
unlike physiological conditions. The first condition is when the 
energy of an outside stimulus reaches the centre. As we have 
seen, it appears probable that in such a case consciousness 
results only when the motor response is partly but not fully 
produced; only when excitation is partly balanced by inhibi- 
tion. The second condition is when energy travels to the sen- 
sory centre directly from another sensory centre. But if the 
mere passage of the nervous process from one sensory centre to 
another is sufficient to call up a conscious process; if, that is, 
the traversing of a sensory centre by a nervous process com- 
ing from another sensory centre and on its way to a third 
is sufficient to bring an 'image' into consciousness, why is 
not the passage of the nervous process through a sensory 
centre on its way to a free motor outlet sufficient to cause con- 
sciousness in the case of the peripherally excited process? Yet 
we have noted the probability that the traversing of a sensory 
pathway by the nervous process is unaccompanied by con- 
sciousness when the motor pathway is free. On hypothesis a, 
then, the conditions for consciousness produced by outside 
stimulation, on the one hand, and the conscious processes, 
* centrally excited,' involved in memory and imagination, on 
the other hand, would be quite unlike: the former would de- 
mand not merely the traversing of a sensory centre by a nerv- 
ous current, but the partial inhibition of a motor discharge: 
the latter would demand merely the passage of the nervous cur- 
rent through the sensory centre from another centre. 

Other arguments agamst hypothesis a will present them- 



30 



MOVEMENT AND MENTAL IMAGERY 




FIGURE 1 



selves later on. Hypothesis 6, that each of the centrally excited 
processes which make up a train of images or thoughts has its 
own special motor response upon whose initiation it depends, 
may now be further developed. 

Suppose that a certain motor pathway, M, has at various 
times in the past been excited by energy reaching it from two 
different sensory pathways, S and S\ 
And suppose that in a given case energy 
from S reaches it, the effect of which is 
partly compensated by an inhibition 
from some antagonistic centre. M will 
then be in the kind of incomplete exci- 
tation which according to the conclusion 
of our last chapter is accompanied by 
consciousness of the sensation S. But 
whatever reason there may be for think- 
ing that a process, accompanied by con- 
sciousness, is set up in S by the incipient excitation of if, would 
appear to hold also for the setting up of a process in S', a centre 
which is not now receiving any excitation from outside, but 
which has formerly, under the influence of outside excitation, 
discharged into M, The very same process which, on our hy- 
pothesis, when added to the effect of an outside stimulus makes 
that effect conscious, will, when it occurs in a sensory centre 
that is not being externally excited, be accompanied by the 
type of consciousness that we call * centrally excited,* the con- 
sciousness that occurs in mental images and thoughts. When- 
ever a motor pathway is at the same time excited by a sensory path- 
way and partially inhibited by an antagonistic motor excitation, a 
process occurs in all sensory pathways connected with the motor 
pathway by low synaptic resistances, including the sensory path- 
way that is exciting the motor pathway in question. This process 
is accompanied by consciousness. When it occurs in a sensory 
pathway that is being excited by an outside stimulus, it gives rise 
to the type of consciousness that we call a peripherally excited 
sensation. When it occurs in a sensory pathway that has no out- 



MOVEMENT AND THE IMAGE 31 

side excitation, it gives rise to the type of consciousness that we call 
a centrally excited sensation or a mental image. ^ 

How, under this hypothesis, can we explain the occurrence of 
a train of images or centrally excited processes, each one calling 
up the next? During the period between the getting of a stim- 
ulus to action and the carrying out of the action, a man's 
thoughts drift from one idea to another: he may in thirty sec- 
onds or so have a long train of conscious processes without any 
external stimulus. In the psychological laboratory, we ask stu- 
dents to take a certain word as a starting-point, and to intro- 1 
spect, without controlling, the images which follow one another 
through their minds. 

On the theory which we are developing, such trains of cen- 
trally excited processes depend on the type of movement asso- 
ciations which we have called * successive movement systems.* 
Take as an example the case of learning a series of nonsense 
syllables which are visually presented, printed or written, be- 
fore one. For the sake of simplicity let us neglect the part 
played by auditory sensations, peripherally or centrally excited, 
and consider the process of pronouncing the syllables, as one 
looks at them, simply as a motor process whose stimulus is 
visual. In reading the series through we have a succession of 
visual stimuli, each followed by its proper motor response. 
Now, as the series is repeatedly read, each motor process comes 
to have two stimuli: the original visual one, the sight of the 
printed or written syllable, and also the kinsesthetic 'feel' of 
pronouncing the syllable just preceding. The more thoroughly 
the series is learned, the more the kinsesthetic stimulus becomes 
sufficient by itself, without the visual one, to set off the move- 
ment. When the series is thoroughly learned, one can say it 
'without book,' that is, without any visual stimuli at all. If, 
however, in reciting a series of syllables without the copy before 

* In an article (146) which I published a year or so ago I suggested that the 
nervous basis of the centrally excited sensation might be a discharge of the 
nervous energies stored up in a sensory centre, induced by the excitation, from 
some other source, of a motor pathway into which that centre had formerly 
discharged. I still think this a possible hypothesis. 



32 MOVEMENT AND MENTAL IMAGERY 

one, there is a delay; if soine inhibition arises, then one may 
recall the look of the missing syllable, more or less accurately; 
that is, delay in the discharge of a motor centre produces, in 
the sensory centre which formerly discharged into it, that 
process upon which there is based consciousness of the sensa- 
tion, centrally excited, which would be peripherally excited if 
an actual stimulus were acting on the sensory centre and its 
motor response were delayed. 

This is what happens, we may suppose, when the series of 
syllables is actually being recited; that is, when the movements 
of articulation are being fully performed. If a hitch comes in 
the recitation, a mental image of the look of the syllables may 
be recalled. What, now, takes place when the series is not re- 
cited aloud, or even whispered, but merely * run through * men- 
tally.^ The thoughts or images which we have fancied to occur 
in the mind of the man deliberating whether he shall write a 
check do not take place, each of them, in the course of a series 
of actual movements that are visible externally. But neverthe- 
less, — and this is a crucial assumption for our whole hypothe- 
sis, — there probably are, going on in his muscles, slight actual 
contractions. So when we mentally run over a series of non- 
sense syllables that we have learned by heart, it must be 
supposed that slight actual movements of the articulatory 
muscles do occur. Introspection furnishes some evidence 
of the fact. Try, for instance, the following test: pronounce 
aloud or in a whisper the letter * b ' successively twenty-five 
times, and as you pronounce it try, absolutely simultaneously, 
to think of each of the other letters of the alphabet. You 
will find that, whether you think of them in auditory or visual 
terms, whether you mentally hear them or mentally see them, 
you have to slip them in between your pronunciations of * b ' : 
the sequence of events in your consciousness has to be *b a,' 
* b c," b d,' and so on. Or try James's old experiment of holding 
the mouth open and thinking of the word * bubble.' In this 
case, to my introspection, the auditory image is impossible, but 
I can form pretty well a visual image of the word. In general. 



MOVEMENT AND THE IMAGE 33 

visual images of words are not so closely dependent on articu- 
latory movements, whether strong or weak, as auditory images 
are, for all visual images are related also to other movements, 
as for example movements of the eyes. 

Slight but actual movements occur when we are thinking. 
These movements it is difficult to christen by a suitable name, 
but for convenience of reference, we shall call them 'tenta- 
tive movements.* A later chapter will be devoted to their 
consideration. 

A train of associated ideas, each one suggesting the next by 
a process which travels directly from one sensory centre to an- 
other, rests according to this hypothesis on a train of move- 
ments each of which, by the kinsesthetic excitations its per- 
formance produces, sets the next one off, while delays in the 
process bring about, in sensory centres that have formerly dis- 
charged into the motor centres now partially excited, the pro- 
cesses on which the images are based. The case is fundamen- 
tally the same whether the movement system consists of 
movements that are being fully performed, though hesitatingly, 
or of tentative movements; whether the series of syllables is 
recited or only thought of. 

Two points in favor of some such hypothesis may be noted. 
The older view demanded that there should exist nervous path- 
ways directly connecting one sensory centre with another. 
Now, in those lower regions of the nervous system of verte- 
brates which have been the subject of exact physiological in- 
vestigation and experiment, there is no evidence that sensory 
centres ever have pathways of direct connection with one an- 
other. * Association pathways ' connect an afferent or sensory 
pathway with an efferent or motor pathway. Several sensory 
pathways converge on a single motor pathway, their * final 
common path,' or upon * internuncial pathways' leading to a 
final common path, but nowhere does any path directly bridge 
across from one afferent path to another. Yet apparently such 
connections would be as useful in the lower regions of the nerv- 
ous system as they are supposed to be in the upper, cortical 



34 MOVEMENT AND MENTAL IMAGERY 

regions. Simplicity would argue for the supposition that all 
parts of the nervous system are built on the same general plan, 
and that this plan involves the association of movements, but 
not the direct association of sensory processes. 

A second argument for the kind of hypothesis we are trying 
to form is this: The older view supposed not only that direct 
pathways connected one sensory centre with another, but that 
when the two sensory centres were simultaneously excited, the 
resistances along the connecting pathway were lowered, so that 
at a later occasion, when a nervous process occurred in one of 
the centres, it travelled across to the other centre and * cen- 
trally excited' it. Thus was explained the fact of experience 
that in order for one thing to recall another to our minds, by 
central excitation, we must have encountered the two things 
together. In order that the sight of a word printed in a foreign 
language shall recall its correct pronunciation, we must have 
heard the word pronounced on some former occasion while we 
were looking at it. But the older view neglected the fact that 
merely experiencing two stimuli together will not suffice to 
form a central excitation tendency. Stimuli may easily act 
simultaneously, each on its own sensory pathway, and the re- 
sistances between these pathways not be lowered at all. For 
example, one needs merely to suppK)se that when looking at 
the foreign word for the first time and hearing it pronounced, 
one hears it only inattentively. If the attention is not directed 
towards the sound, if both the look of the word and the sound 
of it are not attentively experienced, the look will not later re- 
call the sound, nor vice versa. Not the simultaneous experien- 
cing of two objects, but simultaneous attention to them, forms 
a tendency to recall. 

It is clear on our theory why the formation of an * association ' 
demands attention. All association is association between 
movements. Now, when the association between movements 
is in process of establishment, the performance of the move- 
ments is necessarily subject to many inhibitions and delays, 
but of course it must be an actual performance. We must 



MOVEMENT AND THE IMAGE 35 

suppose then that the actual performance of movements — 
that is, something more than the mere innervation of the 
muscles — is what is involved in attention; the excitation 
being weakened and slowed by inhibitions, but nevertheless 
resulting in actual though slight movements. We have seen 
that there are two types of association between movements. 
The first type is characterized by the dropping out of move- 
ments, so that a stimulus takes on a new motor response and 
loses its old one. The second type preserves all the movements, 
and Unks them so that the performance of one furnishes the 
stimulus for the performance of another. Clearly, it is this 
second type of association that is the basis of trains of ideas, 
each one distinguished from the rest, for only where different 
motor responses are initiated are the sensory processes leading 
to them accompanied by distinguishable sensations. 

One of many other points in favor of a motor theory of at- 
tention and the image is that it explains readily what we may 
call the transitory character of both. " The object of attention 
constantly fluctuates." We cannot hold an unchanging thing 
in the focus of attention : it seems to change of its own accord. 
Some years ago in the Vassar laboratory (124) an attempt was 
made to investigate experimentally a phenomenon that nearly 
every one has noticed : the fact that if you look steadily for some 
time at a printed or written word it takes on a strange and un- 
familiar appearance. As our observers gazed steadily at a single 
printed word for three minutes, they noted that the word was 
constantly changing; constantly suggesting new pronuncia- 
tions, new syllable divisions, and so on. * Acre' would become 
*ac-er,' *a-cree,* and so on. This shifting of the object of at- 
tention has been referred to the fact that primitively a stimulus 
must be a change in the environment of an organism, and that 
an unchanging object cannot be a stimulus. But in fluctua- 
tions of attention it is not really the stimulus, not the external 
object, that changes. What changes is our reaction to it, and 
the reason for this constant change of response to a stimulus 
in attention is that the essence of attention is movement, and 



36 MOVEMENT AND MENTAL EMAGERY 

that the great majority of motor processes are of the phasic 
rather than the static or attitude type. 

On our general theory, then, consciousness will depend on a 
certain ratio between excitation and inhibition of the motor 
response to a stimulus; while recall through association will 
depend on the motor response's being sufficiently innervated 
to be actually performed, though only in the weakened form 
of a tentative movement. We may tabulate the different 
ratios of inhibition and innervation of response which ac- 
cording to this theory correspond to different degrees of 
consciousness. 

I. Motor response very slightly excited, not enough to pro- 
duce consciousness. The effects of this excitation appear, 
however, in the phenomenon of * readiness,' which will be 
discussed later. (See page 82.) 

II. Motor response more strongly initiated, but no actual per- 
formance of a movement, either tentative or full. This is accom- 
panied by consciousness of the stimulus, but no associative 
activity can take place, because associative activity requires the 
actual performance of a motor response, to produce the kin- 
sesthetic excitations necessary to set other motor pathways into 
action. 

III. Motor response still more strongly initiated. Tentative 
movements occur slowly and with delays. Consciousness and 
associative activity both present: this is attention. 

IV. Motor response still more strongly initiated. Tentative 
movements occur smoothly and without delay. Associative activ- 
ity occurs, with comparatively little conscious accompaniment: 
these are the conditions which we may think of as underlying 
very rapid thinking, which is nearly unconscious. 

V. Motor response fully initiated and entirely unopposed. 
Performance of full motor response without delay and without 
consciousness: the situation in secondarily automatic or habitual 
actions. 

Thus, by supposing five different ratios of excitation to in- 
hibition, we can make a bridge between the apparently con- 



MOVEMENT AND THE IMAGE 37 

tradictory but equally true statements that unconsciousness 
accompanies total inhibition of movement and that it accom- 
panies perfect freedom of movement. 

Can we form any notion of what physiological process under- 
lies the difference which we consciously experience between a 
peripherally excited sensation and an image? We have assumed 
that the degree of consciousness, what Mlinsterberg would call 
the vividness, of both is due to the same underlying cause, the 
relation between the excitation and the inhibition of the motor 
pathways with which their sensory pathways are connected. 
Now, just what makes the difference between the color red as 
I see it before me and the color red as I remember or imagine 
it? Certainly it is not a difference in consciousness degree. The 
degree of consciousness depends on attention: but I may be 
wholly inattentive to the colors I am actually looking at, and 
fully absorbed in the color imagery that my imagination 
conjures up. If you ask me afterward what I thought of a cer- 
tain red cushion, I may have no recollection that any such ob- 
ject was near me, although I spent some minutes apparently 
looking intently at it. 

All authorities are agreed that centrally excited sensations 
are much less steady and enduring than peripherally excited 
sensations. I cannot hold in consciousness the image of red 
nearly so long as I can be conscious of the red that I actually 
see. On oiu* theory, this short duration of the image is due to 
the fact that the stimulus which initiates the motor response on 
which consciousness of the image depends is produced by an- 
other movement; while the stimulus which initiates the motor 
response on which the peripherally excited sensation depends 
is an outside physical force. It is obvious that a stimulus sup- 
plied by a bodily movement must be of brief duration, unless 
indeed the movement is not a true movement, but a static 
motor process or attitude. Much discussion has centred about 
the problem as to whether a difference in intensity is character- 
istic of the difference between a sensation and an image. To 
immediate observation it seems clear that the color or tone or 



38 MOVEMENT AND MENTAL IMAGERY 

smell one imagines is never so intense as an actual sensation. 
Now, it is not so easy as one might suppose to decide exactly 
what is meant by intensity. 

Schaub's (122) observers, in an introspective study of the 
intensity of images, made the following reports: the images 
*'lack volume, that is, concomitant muscular and organic 
sensations"; "with the sensations there are kinassthetic ac- 
companiments which are not present in the image"; "images 
exactly like the sensations in intensity, but . . . they did not 
give the kinsesthetic shock that accompanied the stimuli.'* 
There seems introspective evidence that when an outside 
stimulus acts on the organism, it sets up, not only a definite 
motor response that belongs peculiarly to it, but also a more 
generalized and diffused motor response, an 'all over ' disturb- 
ance. This general disturbance is felt in consciousness some- 
times as fused with the sensation proper to the stimulus, if 
the kinsesthetic and organic sensory excitations which it sets 
up do not produce a special motor reaction of their own; some- 
times it is attended to on its own account, and more or less 
analyzed into localized components. Whether analyzed or 
unanalyzed, the kinsesthetic excitations coming from this gen- 
eral motor disturbance are probably the basis of a characteristic 
difference between the sensation from an outside stimulus and 
the recalled image; of what Ziehen (161) has termed the "sen- 
sual vivacity" of a peripherally excited sensation, and Stout 
(134) calls the "aggressive character" of a sensation as com- 
pared with an image. It is true that Stout, although he admits 
that when an outside stimulus acts, "the whole organism re- 
ceives a shock giving rise to a mass of organic and kinaes- 
thetic sensations," expressly denies that these can be responsible 
for the aggressiveness of the sensation. But his objection does 
not seem well taken. He says: "It seems evident that they [the 
kinsesthetic and organic sensations] cannot give an aggressive 
character to the experience unless they possess this character 
themselves, and as a matter of fact they are highly intrusive 
and obtrusive. But if organic sensations can * strike the mind' 



MOVEMENT AND THE IMAGE 39 

in this way, there is no reason why other sensations should not 
do so too. The ultimate appeal must be to introspection. This 
shows in the case of the steam whistle [the example Stout has 
been using] that the sound itself is aggressive in the same way 
as the organic sensations which accompany it." But this rea- 
soning confuses an unanalyzed experience with an analyzed 
one. We may reply that the so-called ' aggressiveness ' of a sen- 
sation is merely the name we give to the unanalyzed * feel ' of 
the general organic shock produced by the stimulus; when 
this ' feel ' is analyzed and certain sensational components are 
attended to by themselves, they in turn may perfectly well be 
accompanied by a diffused motor response in addition to the 
special motor response involved in attending to them; if they 
are so accompanied they also are felt as * aggressive.' The same 
answer may be made to Stout's further suggestion that, *'The 
organic sensations follow the beginning of the sound after the 
lapse of about a second, but the sound itself is aggressive from 
the outset." It is the analyzed experience that is thus delayed; 
not the unanalyzed feeling of aggressiveness. 

When an actual outside stimulus, then, is responsible for 
the production of a sensation, the sensation has a certain vi- 
vacity or aggressive character that I shall assume to be due to 
kinsesthetic and organic excitations resulting from a general 
motor discharge. This character is quite evidently stronger, 
and the general motor discharge is more marked, the greater 
the amount of the stimulus: there is no reason why it should 
not be identified with the character of intensity. Shall we, 
then, say that images have no intensity? 

Such a general motor response may be produced, like any 
other movement, not merely by an outside stimulus, but also 
by the setting up of another movement: that is, it can enter 
into a movement system. Thus, I can imagine a very loud 
sound, and when I do so, I feel certain sensations of shrinking 
and shock which are evidently the result of movements pro- 
duced because they are associated with the motor processes 
involved in the idea, * very loud sound.' They are associatively 



40 MOVEMENT AND MENTAL IMAGERY 

produced, and not caused by the action of an outside stimulus 
on my ear. An image may be more or less intense (as distin- 
guished from being more or less clear, having more or less con- 
sciousness degree) according to whether these sensations cor- 
respond to a more or less diffused shrinking and shock. In this 
sense images may possess intensity: I may have the image of 
a louder or a weaker sound. But introspection seems to testify 
that the general motor responses thus associatively produced 
are not identical with the general motor responses that the 
original outside stimulus produced. The general shock and 
strain felt when I imagine a very loud sound are like but not 
identical with those I feel when I actually hear the sound. The 
difference very probably consists in the fact that the associa- 
tively produced shock involves merely the kinsesthetic and 
organic sensations which were analyzed out of the original, and 
that what is missing is the unanalyzed and more diffuse com- 
ponents : it would naturally be the components which were at- 
tended to separately that could readily enter into a movement 
system and so be associatively produced. In any case, while 
the intensity of a mental image consists of the kinsesthetic- 
organic * feel ' of a general motor response, the ' feels ' of which 
image intensities consist are not identical with those of which 
sensation intensities consist. Thus, it is possible, for Ziehen 
to say of "sensual vivacity" as a feature of the peripherally 
excited sensation that it " does not belong at all to the idea, not 
even in a diminished intensity," and for Schaub's observer to 
state that the image was just like the idea in intensity, but did 
not give the same kinsesthetic shock. 

Before we proceed to a fuller discussion, much needed, of the 
subject of tentative movements, it will be well at this point to 
consider a little further the state of affairs described under II, 
above: the case where the motor response is very slightly ini- 
tiated, not enough to produce any actual muscular contrac- 
tion, either tentative or full. This, it was said, produces con- 
sciousness of the stimulus, but under such circumstances the 
sensation resulting can suggest nothing associatively. Now, 



MOVEMENT AND THE IMAGE 41 

suppose that a number of stimuli are simultaneously acting on 
the organism, and that each of them is exciting its appropriate 
motor response to precisely this degree. The result for con- 
sciousness will be a fusion or blending of sensations which is 
recognizably a complex phenomenon, but is not analyzed. We 
may say that when the conscious state at a given moment is 
felt to be complex and not simple, even though the complexity 
is not analyzed into its component parts, the reason is that a 
number of different motor responses are very slightly initiated. 
As soon as one begins to analyze such an experience, one of 
course attends to its parts successively, and the motor excitation 
belonging to each part attended to passes from stage II to 
stage III; to the stage, that is, where it becomes an actual 
tentative movement. Thus, for example, we hear a musical 
chord. It makes upon us a complex impression, even before we 
analyze it into its constituent tones; this complexity is due to 
the fact that a number of different motor responses are very 
slightly excited. When one analyzes the chord, one gives atten- 
tion to its tones successively, making tentatively the motor 
response belonging to each. 

All unanalyzed complexity of experience depends on the 
simultaneous initiation of different motor responses, none of 
them carried to the point of actual performance, even as tenta- 
tive movements. A fine example of the truth of this statement 
is furnished by the phenomena of single and double images in 
binocular vision. When you hold up one forefinger about a foot 
from the eyes, and look at it, the other forefinger, if held at 
either a greater or a less distance from you, will appear double. 
Now, according to our principle, a single object is one which 
initiates a single movement; an object can be perceived as two 
only if it initiates two movements. The law under which ob- 
jects are seen singly by the two eyes is generally stated as fol- 
lows : if the images of the objects fall on corresponding points of 
the two retinas, they will blend into one; otherwise they will 
produce double vision. Corresponding points are points that 
would coincide if one retina could be placed directly over the 





42 MOVEMENT AND MENTAL IMAGERY 

other; thus, evidently the centres of the two retinas are cor- 
responding points, and so are any two points that he at equal 
distances from and in the same direction from the centres of 
the two retinas. Now, it is clear that when the images of an 
object fall on corresponding points, they suggest absolutely 
identical movements of the two eyes. The movement that 
regularly tends to be initiated when an image falls on a point on 
the retina is the movement which would be required to bring 
the image from that point to the centre of the retina, since it is 
when an object casts its image on the centre of the retina that 
-' it is most clearly 

/ T T seen. If, for ex- 

'^^ *\ *r^^^^^''^^>s^ ^ ample, the images 

fall on the corre- 
sponding points a 

^^„„ „ and a', the move- 

FIGURE 2 /. , 

ments a — / and 

a' — /' are initiated, movements precisely equal in extent and 

direction: practically a single movement of the two eyes. But 

if the images fall on points a and 6', non-corresponding points, 

then the movement a — / will be initiated for one eye, and the 

movement h' — / for the other eye. These are movements in 

opposite directions, unlike movements; hence, may we not say, 

the object is seen as double? 

Two further considerations may be noted. First, on our 

theory of the nature of the associative process, evidently two 

sensory centres or pathways must be connected with one and 

the same motor pathway, to give rise to a centrally excited 

sensation or image. For the centrally excited process is due to 

the partial excitation of the motor pathway belonging to the 

sensory centre which is centrally excited, through the action 

upon it of another, a kinsesthetic, sensory pathway. In the 

diagram, on page 30, we may assume that the sensory centre 

5 is kinsesthetic. The excitation of Jf, meeting a certain 

amount of inhibition, sets up a process in *S', which at some 

former time has discharged into M; the accompaniment of this 



MOVEMENT AND THE IMAGE 43 

process is a centrally excited sensation or image of the proper 
stimulus oi S. At the same time, according to our theory, there 
should be peripherally excited consciousness corresponding to 
the kinsesthetic pathway's excitation. Thus, in every centrally 
excited or image process there would be two components, one 
kinsesthetic and one of the modality to which the image is re- 
ferred; in every centrally excited visual sensation, for instance, 
there would be a kinsesthetic and a visual factor; in every cen- 
trally excited auditory sensation a kinsesthetic and an auditory 
factor. These factors need not, however, be for consciousness 
in any way distinct, since distinctness for consciousness in- 
volves the excitation of two different motor responses, and the 
kinsesthetic and non-kinsesthetic components of the process 
underlying the image need not give rise to different motor re- 
sponses. The interesting point, however, is this. As the asso- 
ciative processes run more and more smoothly; as thinking 
becomes easier and easier along a familiar line, as the motor 
responses pass from stage III to stage IV, and the delay be- 
comes less, it is easy to suppose that the non-kinsesthetic path- 
ways become less and less involved, and that the conscious 
accompaniment of thinking becomes less and less composed 
of centrally excited visual, auditory, and other non-kinses- 
thetic processes, and more and more composed of peripher- 
ally excited kinsesthetic processes. Thus we may be able, in a 
later chapter, to understand the fact that thinking tends to 
become 'imageless' in proportion as it becomes more rapid. 

Secondly, the most natural explanation, on a theory which 
bases the image on the movements made in connection with 
attention, for individual differences in type of imagery is that 
they depend on individual differences in the appeal of certain 
kinds of stimuli to attention. A person thinks in visual imagery 
habitually if he habitually attends to the look of things; he 
thinks in auditory imagery if he habitually attends to the way 
things sound; he is clearly aware of his own tentative move- 
ments if he is in the habit of attending to movements. What 
determines the habit of attending to visual stimuli more than 



44 MOVEMENT AND MENTAL IMAGERY 

to auditory stimuli may be either the nature of one's occupa- 
tion, or the development of one's sensory apparatus. A person 
whose eyesight is not good would not be expected to have 
his attention readily attracted to the appearance of things, and 
would probably not belong to the * visual type ' as regards his 
imagery; if, however, with the aid of eye-glasses he were a 
great reader, his visual imagery for words would probably be 
far in advance of the rest of his mental pictures. A person with 
keen eyesight, whose profession did not involve the use of 
visual imagery, would probably have much less of it than, say, 
an architect or a painter. A person who has poor discrimina- 
tion for musical tones and intervals, that is, whose auditory 
sensory apparatus is poorly developed, would have less audi- 
tory imagery for that reason, although he might increase his 
powers of imaging sounds if his profession demanded attention 
to sounds. ' Imagery types ' and their variations and anomalies 
may, I think, be most readily explained as attention types, due 
to innate differences in sense discrimination and to habits 
formed by the nature of one's environment and work. 

It is evident that this theory of the motor basis of conscious- 
ness, whether centrally or peripherally excited, requires, for 
a creature like man, with an immense variety of sensory dis- 
criminations, a great variety of movements. Every stimulus, 
in so far as it is discriminated from other stimuli, excites a motor 
response different from that which other stimuli excite. It is 
possible, indeed, that two stimuli may be consciously dis- 
criminated and still produce the same externally visible move- 
ment : a person may reach for two different kinds of food with 
equal vigor and enthusiasm and yet be perfectly aware of their 
difference. But the motor reactions in such a case are complex, 
and, while outwardly alike, the inner components may well be 
very different : the person, for instance, may be mentally naming 
the two kinds of food. If the whole motor response were the 
same for two kinds of stimuli, then our theory assumes that 
they would not be in any sense discriminated. To have a 
variety of sensations and images, then, demands a variety of 



MOVEMENT AND THE IMAGE 45 

movements. Let us very briefly survey our motor stock in 
trade. 

The muscles of the limbs acquire very few new movement 
systems in the course of a lifetime, and their movements have 
little variety. Those of the hands, however, are quite another 
matter. The most complicated and varied kinds of finger 
movement systems that we acquire are of two types. There is, 
first, the type where an object is held between the thumb and 
one or more other fingers, and moved in various directions. 
These are the movements which we use in forming written 
letters, holding a pen or pencil; in drawing, in using delicate 
tools. They form successive movement systems; in the case of 
writing or drawing, the movements leave behind them per- 
manent visual stimuli, so that visual imagery tends to be last- 
ingly associated with them. Secondly, there is the type of 
movement which consists in pressing down with the finger tips, 
using different fingers successively. In typewriting common 
words like *and,' *the,* and many others, firmly established 
successive movement systems are formed, and in learning a 
piece of music by heart the finger movements involved in 
various phrases become w^ell organized into systems. 

The muscles of the face have a certain number of innate 
movement systems. These were originally all phasic systems, 
it may be supposed, giving rise to changes of facial expression 
in connection with various stimuli of importance for welfare: 
Wundt has shown how, by the operation of the principle of 
analogy, movements originally connected with accepting and 
rejecting certain smells and tastes have become associated with 
other agreeable and disagreeable stimuli. It is noteworthy 
that facial expressions tend to become static rather than phasic. 
An expression originally appropriate to a temporary emotion 
becomes fixed and permanent. The reason for this is probably 
that the facial muscles are little needed and may remain at rest 
for long periods of time: a phasic system of arm movements, 
obviously, could not afford to become static, since the muscles 
would be called into activity in other combinations. 



46 MOVEMENT AND MENTAL IMAGERY 

The eye muscles are an extremely interesting system from 
the point of view of the movement systems into which they 
enter. The fixation of the eye in any position may involve a 
simultaneous static movement system; that is, a true attitude, 
requiring the steady contraction of certain muscles. The un- 
opposed contraction of the external rectus muscle, for instance, 
would move the eye away from the nose until the limit of 
the muscle's contraction was reached : if any point between the 
centre of the field of vision and the extreme side is fixated, 
the contraction of the external rectus is balanced by that of the 
internal rectus, and the contractions have to be maintained as 
long as fixation is maintained. Binocular fixation also means 
a static movement system, involving varying degrees of steady 
contraction on the part of the two internal recti, acting to- 
gether and producing convergence of the eyes. The eye move- 
ments by which lines are explored are, as we have seen, while 
not successive movement systems themselves, the basis of the 
formation, between the other movements made in response to 
visual stimuli, of double successive systems with reversed 
order, the characteristic basis of spatial perceptions. 

The articulatory muscles furnish us with the greatest variety 
of movement systems, a variety that is practically unlimited. 
We have only to consider that it includes at least all the words 
and phrases that can be uttered in any language spoken on the 
earth's surface, to realize its enormous range. There is nowhere 
else in the body a region capable of anything like such versatil- 
ity: the movements of the fingers, complicated as their com- 
binations may be, have not the same varied character to start 
with; their combinations must be formed out of a much smaller 
number of simple movements. In speech the single sounds 
are produced by means of simultaneous phasic systems. The 
sound of broad a, for example, results from the simultaneous 
vibration of the vocal cords and a certain position of the cheek 
muscles and the tongue. The guttural g is produced by a cer- 
tain position of the glottis and a slight vibration of the vocal 
cords. A word involves a successive system made up of the 



MOVEMENT AND THE IMAGE 47 

simultaneous phasic systems that constitute the letters; a 
phrase, a sentence, a stanza of poetry learned by heart, are 
still longer successive systems. The slight degree of physical 
effort which the use of speech muscles involves, and the fact 
that they are not often required for ministering to immediate 
practical needs, makes possible the repetition of a given move- 
ment system so often that it may be very quickly and firmly 
established. Another characteristic feature of articulatory 
movements is that they so commonly produce audible effects, 
which for a given movement are absolutely constant in char- 
acter. Very commonly as a successive system is formed out of 
speech movements, the auditory pathways excited by the per- 
formance of the first movement join with the kinsesthetic path- 
ways in exciting the second. This is surely the reason why kin- 
sesthetic excitations from speech movements, if accompanied by 
consciousness at all, seem to involve some auditory imagery. 
Of the greatest significance for the structure of our experi- 
ence are imdoubtedly the motor processes which go on in the 
internal organs. The general organic response to a stimulus 
furnishes masses of kinsesthetic excitation which we cannot 
analyze in many cases, but which are probably highly varied 
and capable of representing, in movement systems, the different 
individualities of many stimuli and combinations of stimuli. 
The possibility that the peculiar motor effect of a stimulus on 
the organism as a whole may be the basis of the recall of men- 
tal imagery has not escaped psychologists. Betz (11), in par- 
ticular, says that one experience recalls another when they 
set up the same Einstellung or attitude, and this Einstellung 
seems to include the total motor effect of the experience, not 
only word movements, but "finer organic movements," and 
feelings. As an illustration of an Einstellung which in a given 
case accompanied the recognition of a face he mentions the 
tendency to laugh. Muller-Freienfels (92), also, makes the 
* attitude' into which an object throws us, and which involves 
apparently as its most characteristic features organic processes, 
the essential thing for both perception and recall. 



CHAPTER IV 

TENTATIVE MOVEMENTS 

The point where the theory regarding the nervous basis of 
consciousness, attention, and the image which has just been 
outUned departs furthest from generally accepted psychological 
doctrine is in the supposition that when a stimulus is attended 
to, not only is there initiation of a motor response peculiar to 
that stimulus, but slight actual performance of the movement. 
Thus, to take a simple example, when one attends to the sound 
of a tone sung by another voice, our theory supposes that there 
is slight actual movement in the muscles required to sing the 
tone oneself. These slight actual movements give rise to 
kinsesthetic excitations, which when they affect consciousness 
are felt as kinsesthetic or movement sensations; thus, we can 
find some introspective verification of the existence of such 
movements when we listen to the tone; we can feel sensations 
in the vocal organs. But our theory would suppose that even 
when the kinaesthetic excitations do not affect consciousness 
and thus cannot be detected by introspection, they yet are 
present and perform an important function. I have chosen the 
term ' tentative movements,' for want of a better name, to in- 
dicate these slight actual movements, peculiar to a given stimu- 
lus, which accompany attention to that stimulus. 

Let us see once more just why we have found it necessary to 
assume the existence of tentative movements. We get a pe- 
ripherally excited sensation when a motor response belonging 
to the stimulus for the sensation is delayed. We get a centrally 
excited sensation when a motor pathway into which a certain 
sensory centre has formerly discharged is partially excited from 
some other source. Two sensations, whether peripherally or 
centrally excited, are consciously discriminated only when 
their motor responses are different. If their stimuli lead to the 



TENTATIVE MOVEMENTS 49 

same motor response, they are, for the time being at least, in- 
distinguishably fused for consciousness. It follows, then, that 
the basis of a train of mental images or centrally excited proc- 
esses must be the excitation of a train of motor responses : the 
sensory centres concerned with the images are not directly 
excited one by another, but are excited through the arousal 
of their motor responses one by another. And there is no way 
in which one motor response can directly excite another except 
through the kinaesthetic excitations it produces : that is, it must 
actually be performed; there must actually be some process in 
the muscles, to give rise to a sensory current that can excite 
the other motor pathway. This, at least, must be the case for 
all associations that are of recent formation. It may be that 
acquired movement systems become after a while so thor- 
oughly organized that a direct connection is established be- 
tween the motor centres concerned, so that the excitation of one 
immediately excites the others, without the intervention of any 
kinaesthetic processes; such is doubtless the case with innate 
movement systems. But trains of ideas occur on the basis of 
associations much less thoroughly practiced than they would 
have to be to arrive at this stage of organization. And these 
trains of ideas must, unless the whole motor theory is wrong, 
involve the kinaesthetic excitations resulting from actual move- 
ments. 

It is only in certain cases, however, that we can get intro- 
spective evidence of the sensations from such movements. 
Sometimes, as we follow a train of thought or imagery, we 
can detect inner speech by slight movement sensations in the 
vocal organs, or slight sensations from eye movements, or 
slight shrinkings, strains, and relaxations in more widely dis- 
tributed muscles. In other cases, one idea will give rise to an- 
other so quickly that no introspection can detect sensations 
from any motor process. Now, here is a curious point. When 
introspection has put on record such kinaesthetic accompani- 
ments of thinking, it has commonly described the sensations 
as 'centrally excited,' as kinaesthetic images and not sensations 



50 MOVEMENT AND MENTAL IMAGERY 

from actually performed movements. All the introspective 
testimony to the presence of kinsesthetic factors is simply, it 
may be urged, testimony to the effect that we remember or 
imagine the movements concerned, not that we actually per- 
form them. To prove that they are actually performed, we 
should have to argue that there is no such thing as a centrally 
excited movement sensation: that all cases of so-called kinces' 
ihetic imagery are really cases of 'peripherally excited movement 
sensation resulting from the actual slight performance of move- 
ments. 

It is universally admitted that kinsesthetic images have a 
marked tendency to result in actual movement, and thus to 
transform themselves into peripherally excited sensations. 
" Every representation of a movement," says James (57, Vol- 
ume II, page 526), " awakens in some degree the actual move- 
ment which is its object"; a statement which we should modify 
by saying that the representation of the movement has no exist- 
ence apart from the sensations resulting from the actual move- 
ment *in some degree' aroused. "It is well known," says 
Beaunis (9, page 138), "that the idea of a movement suffices to 
produce the movement or make it tend to be produced." 

Strieker has furnished psychology with a classic example of a 
person whose kinsesthetic processes are habitually clear in his 
consciousness; who is in the habit of attending to them and can 
readily detect them by introspection. He could easily note 
them, not only when he was thinking of objects as being moved, 
— when, for example, he lay on a couch and thought of a per- 
son walking, in which case "feelings in the muscles" were very 
clear to him, — but when he imaged any process of change. He 
says (136, page 18): "When I imagine that a yellow object 
becomes blue, I can imagine the yellow and blue side by side 
without thinking of a muscle. But when I think of the yellow as 
giving place to blue, I must have recourse to muscle feelings: 
the thing is done with the aid either of the eye muscles or the 
muscles of the back of the neck." Now, the possibility occurred 
to Strieker that these "muscle feelings" which were so notice- 



TENTATIVE MOVEMENTS 51 

able a part of his experience in general were the results of actual 
muscular contraction, and that there is no such thing as a 
remembered or centrally excited kinesthetic sensation. One 
might think, he says, that in the centre for muscle feelings there 
is no residue left behind which can make a memory possible: 
that when one associates a muscle feeling in memory it always 
has to be produced over again: precisely our position, that 
kinsesthetic processes are always peripherally and never cen- 
trally excited. And his objection to this conclusion does not 
touch our own theory. He urges that surely traces of past mus- 
cular feelings are left behind, for there is the fact of practice: 
there is the fact that when in humming an air he comes to a 
point where he can't remember it, he can often take his fiddle 
and play it (136, page 36). Evidently, we can reply to this, the 
fact of practice, that a movement is more readily performed 
each time it is repeated, has nothing to do with the power to 
call up a mental image of a movement without actually per- 
forming it. Indeed, the two processes of habit formation 
through practice and the recall of images vary inversely with 
each other in general: the more thoroughly a movement is 
practiced the less imagery of any sort accompanies it. We 
need not conclude, then, that because motor memory, in the 
sense of habit formation through lowered resistances at syn- 
apses, exists, therefore kinsesthetic image memory, which 
would require a fairly high degree of synaptic resistance, is 
necessarily possible. 

In Ach's (2) experimental studies on the will, he develops a 
peculiar conception which he calls that of intentional movement 
sensations. They are one of the characteristic features, he 
thinks, of a voluntary act. They occur in the interval between 
the forming of a resolution and the execution of it, provided 
that there is such an interval of delay, occasioned either by 
opposition to the carrying out of the movement or by lack of 
practice in executing it. They determine the direction in which 
the movement is to be carried out : they can exist only weakly, 
as indications (andeutungsweise), without resolving themselves 



52 MOVEMENT AND MENTAL IMAGERY 

into actual movement, and the transition from them to actual 
movement is perfectly continuous. Hence, Ach says, they have 
often been wrongly called * innervation sensations.' But they 
are not the peripherally excited results of actual movements, 
Ach thinks, for the following reasons. First, they occur before 
the actual movement. We might answer that the weak tenta- 
tive movements which we are assuming may precede the actual 
movement, understanding by the latter term the full execution 
of the movement; and yet the tentative movements may be 
actual as well as the full movement. Secondly, Ach urges, they 
occur when no movement follows. This fact, we may reply, does 
not mean that they are not movements themselves. Finally, 
the most serious of Ach's arguments against the peripheral 
origin of his intentional movement sensations is that they were 
not abolished by suggested anaesthesia of the part to be moved. 
That is, a patient was hypnotized and given the suggestion 
that his hand and arm were insensitive: the suggestion was 
accepted, but intentional movement sensations were still ob- 
served. Even this argument is not conclusive, however, for it 
is hard to be sure that the suggestion abolishes all sensations 
from the part affected; suggestions are so difficult to make 
thoroughgoing. One recalls the case quoted by Sidis (128) 
where a patient was told under hypnosis to have no more slight 
headaches and proceeded to have a severe one. 

In his Experimental Psychology of the Thought Processes (137), 
Titchener says that while he once wrote a paper in which he 
expressed his inabihty to discriminate between a kinesthetic 
sensation and a kinsesthetic image, he has now found a criterion 
which distinguishes them. "Actual movement," he main- 
tains, "always brings into play more muscles than are neces- 
sary, while ideal movement is confined to the precise group of 
muscles concerned. You will notice the difference at once — 
provided that you have kinsesthetic images — if you compare 
an actual nod of the head with the mental nod that signifies 
assent to an argument, or the actual frown and wrinkling of the 
forehead with the mental frown that signifies perplexity. The 



TENTATIVE MOVEMENTS 53 

sensed nod and frown are coarse and rough in outline; the im- 
aged nod and frown are cleanly and dehcately traced. I do not 
say, of course," he continues, "that this is the sole difference 
between the two modes of experience. On the contrary, now 
that it has become clear, I seem to find that the kinsesthetic 
image and the kinsesthetic sensation differ in all essential re- 
spects precisely as visual image differs from visual sensation. 
But I think it is a dependable difference, and one that offers a 
good starting point for further analysis'* (pages 20-21). We 
should say that this difference between the coarse, roughly out- 
lined movement which brings into play more muscles than are 
necessary, and the clear-cut delicately traced movement that 
involves only a precise group of muscles, is the difference, not 
between centrally excited kinsesthetic sensation, remembered 
but not actually performed movement, and movement that 
actually occurs in the muscles, but between slight, tentative 
muscular movements, and large, visible, fully executed ones. 
And why, one must always ask the partisan of movement im- 
agery, is it so hard even for Titchener to distinguish between the 
movement image and a slight actually performed movement.'^ 
Perhaps, as he says, they differ just as a visual image differs 
from a visual sensation, but certainly he never felt moved to 
write a paper doubting the existence of a difference between 
visual image and visual sensation. My colleague Dr. Woods 
writes me with regard to her studies of the process of recog- 
nition (156): "My observers admitted an inability to distin- 
guish imaged from real movements to such an extent that I 
abandoned the attempt to separate kinaesthetic image from ac- 
tual movement, and used the term * kinaesthesis ' to cover both." 
Since, then, it is so generally recognized that the border-line 
between image and sensation is obscured for kinsesthetic proc- 
esses, is not the simplest explanation of this difficulty in dis- 
criminating between the mental image of a movement and 
weak sensations from actual muscular contraction, that the 
images really are sensations from slight actual muscular con- 
tractions? 



54 MOVEMENT AND MENTAL IMAGERY 

If we grant that there often exists introspective testimony 
to the existence of tentative movements, what shall we say of 
the cases where introspection can find no trace of any kinses- 
thetic process, either sensation or image? Sometimes, as has 
been said, one idea suggests another when we can discover no 
muscular ' feeling ' at all, either image or sensation. This is true 
of everybody at many moments of experience, and of some 
persons more constantly true than of others. Notice that 
Titchener says, "provided that you have kinsesthetic images"; 
and certainly some j>eople are aware of little or no kinsesthetic 
* imagery.' Strieker furnishes an instance of a person who had 
much awareness of kinsesthetic processes, and he went so far 
as to say (135) that his idea of a word was wholly an idea of the 
movements needed to pronounce the word: whereupon other 
psychologists promptly denied that their verbal ideas were 
kinsesthetic at all. There are evidently two problems for us 
here. First, can we believe that actual tentative movements 
occur of which even the most * motor-minded ' person is uncon- 
scious (ruling out, of course, movements of the internal organs 
which are never normally accompanied by consciousness)? 
Secondly, under what circumstances may we exi>ect that ten- 
tative movements will be represented in consciousness by sen- 
sations? 

There is a great mass of evidence to show that actual move- 
ments of slight extent take place in the voluntary muscles, 
without consciousness of them by the person who performs 
them. One needs only to refer to the literature of * mind-read- 
ing' and to experimental comparative psychology. It is well 
known that many, and probably all, cases of so-called * mind- 
reading' are 'muscle-reading'; that is, that the * mind-reader * 
is able to distinguish by the senses of touch, sight, or hearing 
slight movements of which the subject whose mind is read is 
quite unconscious. A famous English mind-reader, Stuart 
Cumberland (26), said in a popular article written many years 
ago: "In my case * thought-reading ' is an exalted perception of 
touch. Given contact with an honest, thoughtful man, I can 



; TENTATIVE MOVEMENTS 55 

ascertain the locality he is thinking of, the object he has de- 
cided upon, the course he wishes to pursue, or the number he 
desires me to decipher, almost as confidently as though I had 
received verbal communication from him." That unconscious 
movements can reveal themselves to another person's sense of 
sight as well as to his sense of touch was well illustrated by the 
investigation which Pfungst made of Clever Hans, the trained 
horse of Berlin. In order to show that this animal's perform- 
ances in the way of solving arithmetical problems and answer- 
ing questions consisted really in the response to slight move- 
ments unconsciously made by his trainer, Pfungst (108) insti- 
tuted a series of laboratory experiments with human beings, in 
which he found that he could discover what number they were 
thinking of, by beginning to tap with his hand and watching for 
a slight movement of the head that was unconsciously made 
when he reached the right number. When they thought of 
spatial directions such as up or down, right or left, or of 'yes' 
or *no,' Pfungst could similarly determine what they were 
thinking by the head and eye movements they made. Certain 
thought-readers are known to have made use of auditory clues 
furnished by unconscious movements on the part of their sub- 
jects, and it is quite possible that the arithmetical performances 
of the Elberfeld horses, who are able to solve arithmetical 
problems even when they cannot see, are dependent on an 
acute sense of hearing. As a result of such experiences on the 
part of experimenters on animals, it is now a regular practice 
for the experimenter to be always out of sight and when possi- 
ble out of hearing of the animal tested: no statements on the 
part of an investigator that he was sure he made no move- 
ments which could serve the animal as a clue are now accepted, 
for we know that he may have made such movements quite 
unconsciously. 

Our second question was : Under what circumstances may we 
expect that tentative movements will be represented in con- 
sciousness by movement sensations? The answer to this ques- 
tion should explain why some persons are so constantly, and 



56 MOVEMENT AND MENTAL IMAGERY 

every one is occasionally, unaware of such movements when 
they nevertheless actually occur. 

Let us suppose the case where a train of ideas passes through 
consciousness. On our theory, the nervous basis of this train is 
a si^ccessive movement system. The first reaction, made as a 
tentative movement, produces kinsesthetic excitations that ex- 
cite the second motor centre: during any delay that occurs in 
the discharge of this centre, the sensory centre that belongs to 
it is centrally excited, and there occurs an image in conscious- 
ness. When the second centre discharges into tentative move- 
ments, the kinsesthetic excitations which these movements 
occasion excite the third motor centre : and the sensory centre 
belonging to this motor centre is centrally excited, giving rise 
to another image in consciousness. Each motor centre in the 
system is connected with two sensory centres : the kinsesthetic 
one which is excited by the performance of the preceding 
movement in the system, and its own proper sensory centre, 
visual, auditory, or of whatever nature. Now, the conscious 
image resulting from the excitation of a motor centre is thus 
a fusion of kinsesthetic elements with visual, auditory, or other 
sensational elements. In order that the kinsesthetic elements 
shall be distinguished in introspection, in order that the owner 
of the brain whose processes we are describing shall realize that 
any motor processes are going on, the kinsesthetic processes 
must be separately attended to: that is, they must have special 
reactive movements belonging to them. They must produce, 
not simply the next movement in the movement system, but a 
special motor response of their own: for example, the response 
of describing them in language, of saying that they are sensa- 
tions in the larynx or in the eyes; of calling them sensations of 
strain or movement or relaxation. 

Now, there are two cases where attention to movement sen- 
sations is necessary, and where, accordingly, the kinsesthetic 
excitations will be connected, not merely with the other motor 
centres in a movement system, but with responsive move- 
ments of their own. The first and least important is that 



TENTATIVE MOVEMENTS 57 

where there is the special intention to introspect. The nature of 
a special intention or **Aufgahe*' is considered elsewhere (see 
Chapter VIII) . If our definite aim is to observe and discover 
the kinaesthetic factors that are present in, for example, a train 
of ideas, then, as we revive the experience for purposes of 
study, we are constantly interrupting the flow of events by say- 
ing to ourselves 'sensations in the larynx,' 'slight tendency to 
move the lips,' ' strain at the back of the neck,' and so on: that 
is, we make certain motor responses to the kinsesthetic excita- 
tions for their own sakes, instead of allowing them, as they 
ordinarily would, to excite the next movement in the series 
without themselves becoming apparent to consciousness. This 
situation is one peculiar to the psychologist, and is no part of 
the experience of the common man. 

The second case where attention is given to kinsesthetic ex- 
citations for their own sake is the case where a full movement is 
to be made, and made with great care. In this case the move- 
ment first occurs as a tentative movement, and there is a slight 
delay before the tentative movement passes over into complete, 
externally observable movement. In this pause the kinses- 
thetic excitations coming from the tentative movement be- 
come clear in consciousness, are attended to, and thus when the 
full movement is made, and the same kinsesthetic excitations 
occur in greater intensity, the movement is identified as cor- 
rect. (See the discussion of the feeling of incorrectness, page 
202.) It is possible that this was the original function of 
tentative movements, to try a movement before fully executing 
it; and that out of this situation, where a movement is made 
experimentally before being made completely and thus endan- 
gering the welfare of the organism, has grown the function of 
tentative kinsesthetic excitations in producing ideas. If so, the 
later function has now largely overgrown the earlier one. And 
as Strieker has said, those individuals who can with especial 
ease attend to their own movement sensations are apt to be those 
who are much given to bodily exercises; who are, that is, much 
in the way of learning new and hazardous bodily movements 



58 MOVEMENT AND MENTAL IMAGERY 

which need to be performed with great care. It is necessary for 
such persons to be conscious of kinsesthetic excitations. But 
most of us, after childhood, perform few movements that are not 
thoroughly practiced; so we have lost the tendency to attend 
to movement sensations. 

Upon the occurrence of tentative movements and their com- 
bination into simultaneous and successive movement systems 
will be based the whole theory, outlined in this work, of the 
nervous processes underlying the inner life of the mind. All 
thoughts and mental images, all the contents of consciousness, 
rest not simply on delayed full motor response, externally visi- 
ble, but on delays in the systems of tentative movements. 
When these systems run smoothly, we have 'unconscious 
thought'; when delays occur, we have 'sensations* and 
'images.' The precise nature of the physiological process 
which underlies a tentative movement, and the precise differ- 
ence between this process and that underlying a full move- 
ment, it would be useless to conjecture. Is there simply a 
difference in the amount of the nervous energy sent along a 
given motor pathway to the muscles, a less amount producing 
the very slight contractions of tentative movements; or do 
full movements require the action of more neurones than ten- 
tative movements do? The latter alternative must be chosen if 
the ' all or none ' principle, according to which a neurone acts 
either with full strength or not at all, holds for reflexes. (See 
for evidence against this supposition, Brown (16).) 

The actual muscular contractions which we perform in the 
course of a day, then, are some of them full movements, visible 
externally, and some of them tentative movements. The latter 
are always going on; the former, save for the movements con- 
nected with organic processes, may be wholly interrupted by 
long periods of rest. Tentative movements are very economical 
of energy. They involve far less fatigue than full movements, 
and can be performed far more rapidly. They are also not likely 
to bring the organism into danger. A creature capable of ten- 
tative movements can remain in a safe place and escape obser- 



TENTATIVE MOVEMENTS 59 

vatlon, while if the movements were fully performed it would 
risk discovery. 

The first requisite for the development of the nervous ap- 
paratus, whatever it may be, on which tentative movements are 
based, was evidently the ability to suppress or inhibit the full 
movements. A creature, to be capable of tentative movements, 
must be capable of resting apparently motionless under the 
influence of a stimulus which is nevertheless producing an in- 
visible effect. Thus one of the great conditions of higher intel- 
lectual development, as Sherrington (126) and the writer (144) 
have both argued, is the development of sense organs that enable 
an animal to respond to an object not in actual contact with 
the body; distance receptors, to use Sherrington's term. The 
eye and the ear, for example, give warning of the approach of 
objects while they are still a great way off. Now, an object in 
contact with the body must be reacted to without delay: it 
must be seized or avoided, for it is capable of direct and instant 
benefit or injury. But to an object far off one may delay full 
motor response. And only when full motor response does not 
occur can tentative movements be performed. 

Among the higher animals, whose distance receptors are well 
developed and which are capable of keen vision, hearing, and 
smell, tentative movements are still limited in their occurrence 
by the fact that most animals have a very limited repertory of 
movements. You cannot use muscles for tentative and for full 
movements at the same time. Most of the muscles of an animal 
are needed for purposes of locomotion: they have no such ap- 
paratus as our vocal organs, for example, capable of performing 
an almost infinite variety of movements without interfering 
at all with movement of the body as a whole or any other neces- 
sary movements. We can, and some of us do, accompany all 
our physical labors with talk. Moreover, eye movements We 
but little developed in the great majority of animals: where, as 
in the case of many vertebrates, there is no fovea or retinal 
region of clearest vision, there is no need for eye movements. 
We are so impressed with the skill and agility of movements of 



60 MOVEMENT AND MENTAL IMAGERY 

locomotion in the lower animals, whose motor performances in 
this line are so far beyond our own powers, that we overlook 
the comparative simplicity and lack of variety involved in their 
movement systems. But when we consider the number of artic- 
ulate sounds in all human languages, taken together, we realize 
that they are based on a capacity for varied movement that all 
the movements of all the lower animals combined could not equal. 
Finally, it would seem highly probable that the cortex is the 
organ for tentative movements, and that on the development of 
the cortex the development of tentative movements rests. The 
very interesting theory of Head (50) with regard to the func- 
tions of the cortex and the thalamus naturally occurs to one 
in this connection. He believes that consciousness, instead of 
being the accompaniment of only cortical processes in the brain, 
may also accompany processes in the optic thalamus. "There 
are two masses of gray matter, or sensory centres, in which 
afferent impulses end to evoke that psychical state called a 
sensation. One of these is situated in the optic thalamus, whilst 
the other consists of a considerable area of the cerebral cortex." 
"VMien the thalamic centre acts independently of cortical con- 
trol, the motor response is excessive and there is very poor dis- 
crimination; thus the resulting consciousness is of the emo- 
tional type. Attention and all the effects which depend upon it 
are due to cortical activity: "the cerebral cortex is the organ 
by which we are able to focus attention upon the changes 
evoked by sensory impulses." ^ These alleged differences be- 

1 Mr. S. Bent Russell (119), in a criticism of an article of mine (146), has sug- 
gested that kinesthetic impulses from what he calls ' strain signals ' may pass di- 
rectly to cortical sensory neurones and give rise to centrally excited sensations of 
various modalities. His 'strain signals' seem nearly identical with what I have 
called * tentative movements.' He says: "The theory of strain signals assumes 
that a motor discharge that is too faint to cause contraction is strong enough 
to excite certain sensory terminals in the muscles which have communication 
with cortical centres." His use of 'strain signals' differs, however, from my 
use of 'tentative movements' in that I make the kinaesthetic excitations act 
on motor centres to cause the association of movements: he makes them act on 
sensory centres to occasion images. That is, his theory is not based on the 
hypothesis that all association is association between movements. 



TENTATIVE MOVEMENTS 61 

tween thalamic and cortical consciousness are just what we 
should expect to occur if the motor responses from the thalamus 
had to be full responses, while only cortical motor responses 
could be tentative. And it is obvious that our theory regarding 
the function of tentative movements would explain also why in 
Head's words, "the sensory cortex is also the storehouse of past 
impressions." 



CHAPTER V 

THE SPONTANEOUS RECURRENCE OF MOVEMENTS*. THE 
MEMORY AFTER-IMAGE AND PERSEVERATION 

In what we have been saying about the possible nature of 
central excitation and the mental image, it is the revival of 
sensations some time after the action of the original, outside 
stimulus that has been considered. When, in attending to an 
object, we recall the circumstances under which we last en- 
countered it, the assumption is that our previous experience 
with it may have been minutes, hours, days, or years ago. I 
can recall the front door of the house in which I lived ten years 
since, and which I have not seen since I moved away. Now, I 
can also, immediately after looking at the front door of my pres- 
ent abode, shut my eyes and recall its appearance. Is there any 
fundamental difference between a mental image recalled di- 
rectly after the original stimulus has ceased acting, and a mem- 
ory image recalled after a longer interval .^^ Fechner (34) sug- 
gested, for the former kind of mental image, the term * memory 
after-image.' When we glance at a picture and then turn away, 
for a few moments, unless our attention is distracted, it is as 
though the picture were still before us; or perhaps a clock has 
struck unheeded when we were absorbed in work, and presently 
our attention is drawn to its tones still echoing, not in the air, 
but in our consciousness. 

In the case of a visual stimulus, we must evidently draw a 
careful distinction between the memory after-image and the 
sense organ after-image due to retinal processes continuing after 
the withdrawal of the stimulus. After looking at a bright ob- 
ject, such as an electric light or the sky out of a window, on 
closing the eyes we see for a while a bright image still lingering, 
and we are told that this image is due to a retinal process that 
goes on after the original stimulus has ceased to act. That this 



RECURRENCE OF MOVEMENTS 63 

retinal after-image, as a phenomenon of consciousness, is de- 
pendent like all other conscious phenomena on the partial ex- 
citation of a motor response, is shown by the fact that we do 
not see it unless we are attending to it, watching for it; that is, 
unless the appropriate motor response is excited. Fechner men- 
tions in that passage of his Elemente der Psychophysik where he 
uses the term * memory after-image,* several points of difference 
between the visual memory after-image and the retinal after- 
image. Instead of considering these just as Fechner stated 
them, let us ask what differences would most naturally strike 
one in introspecting the two experiences. 

First, it is of course only the positive retinal after-image with 
which the memory after-image could possibly be confused. A 
retinal after-image is sometimes positive, of the same brightness 
as the original, as when on glancing away from an electric bulb 
we see a bright image of the incandescent wire; and sometimes 
negative, or of the opposite brightness, as when we see black 
disks floating before our eyes when we have incautiously looked 
at the sun. Further, the after-image of a colored stimulus 
often appears in the color complementary to the original : if we 
look long at a red disk we shall see a green disk on looking away. 
The negative and complementarily colored retinal after-images 
could never be confused with the memory after-image, for the 
latter always resembles the original. This is one of the points 
of difference mentioned by Fechner. 

Secondly, the positive retinal after-image produced by an 
object of ordinary brightness is very brief and often not notice- 
able at all. An object seen in the shadow, presenting no marked 
difference in brightness from its surroundings, will give no ob- 
servable positive retinal after-image, but its memory after- 
image may be perfectly clear. K the front door of my house is 
in bright sunlight, as I close my eyes after glancing at it I may 
see a very brief positive retinal after-image; if it is shaded, I 
shall probably get no retinal after-image at all, but I can per- 
fectly well hold in attention a very clear memory after-image of 
its appearance. 



64 MOVEMENT AND MENTAL IMAGERY 

Thirdly, the memory after-image represents the original ob- 
ject in its proper spatial relations : solid objects are solid in the 
memory after-image, but the retinal after-image is always 
seen as flat. Fechner quotes from Purkinje's Beitrdge zum 
subjektiven Sehen (page 166), a passage in which the latter con- 
trasts what he calls the after-image and the dazzle-image 
(Blendungsbild) . It is not quite clear just what Purkinje had in 
mind, but Fechner thinks the after-image is what he himself 
means by the memory after-image, and that the Blendungsbild 
is the retinal after-image. "The topic activity of the sense," 
says Purkinje, "the touch sense of the eye, places the after- 
image [memory after-image] outside the organ, as it appeared in 
actual vision; it can also represent images in three dimensions, 
and even with movement and twisting of the whole body, this 
image preserves its original position. The Blendungsbild repre- 
sents surfaces only, is localized in the eye, and follows its move- 
ments.** The last sentence gives a true mark of distinction 
between retinal after-image and memory after-image. While 
the localization of both kinds of images is a highly variable and 
complex phenomenon, it is clear that the retinal after-image is 
always seen as a flat, never as a solid object. 

The most important point to be considered with regard to the 
memory after-image, when compared either with the sense 
organ after-image or with the revived image, is its relation to 
attention. Can a detail of the original object which serves as 
stimulus, unattended to in the original, appear in the image; or 
is the image the faithful reproduction only of what was at- 
tended to in the original? Much discussion has tm*ned on this 
problem, and I think we shall see that sense organ after-image, 
memory after-image, and revived image form an ascending 
series with reference to their dependence upon attention for 
their details. 

In the first place, a very little observation of the retinal after- 
image suffices to prove that in it details appear whether they 
were attended to in the stimulating object or not. Only the 
impression made on the sense organ, not in the least the impres- 



RECURRENCE OF MOVEMENTS 65 

sion made on attention, is the determining condition for the 
retinal after-image. We often note retinal after-images of ob- 
jects which were quite unnoticed in our surroundings : with the 
eyes closed we see a green spot in the field of vision and trace it 
to a red object at which we have been looking with unobserving 
eyes, our attention occupied with something quite different. 
This, says Fechner, is a mark distinguishing the retinal after- 
image from the memory after-image : the former comes whether 
one has attended to the object or not, but the latter represents 
only what has been attended to. Whether this last statement 
is true or not, it seems highly probable from our ordinary ex- 
perience that the revived image, on the other hand, that which 
recurs after an interval of time has elapsed since the original 
stimulation, contains only what was attended to in the original. 
We cannot recall a memory image several hours after an expe- 
rience, and hope by examining it to note peculiarities which we 
overlooked when the experience was first received. Revived 
image and retinal after-image, then, represent opposite poles 
in this respect : the continued activity of the sense organ does 
not depend upon attention, but the activity of cortical centres 
will be revived only if that activity originally occurred under 
the conditions, whatever they may be, which underlie the 
psychic phenomena of attention. 

Now, what is the case with regard to the memory after- 
image ? There is some evidence that it resembles the revived 
image in so far that the elements in the original object to which 
most attention was given are the elements which most pre- 
dominate in the image. Rousmaniere (118), in her experiments 
on Certainty and Attention, exposed for two seconds various 
objects, such as black letters and numbers and colored geomet- 
rical figures, on a gray background. The observer was then 
asked to report what he had seen, stating the degree of cer- 
tainty, on a scale of four degrees, with which he recalled each 
detail. The memory after-image must have been used in mak- 
ing this report. It was found that if the observers were in- 
structed beforehand to attend to a particular feature of the 



66 MOVEMENT AND MENTAL IMAGERY 

figures shown, such as their color, the highest degree of cer- 
tainty belonged to the reports with regard to that feature, in- 
dicating that they were most definitely represented in the 
memory after-image. On the other hand, every observer gave 
some judgments of the highest degree of certainty concerning 
details outside the field attended to; which may mean only that 
attention was involuntarily given to these details, and not that 
although unattended to in the original they were reproduced in 
the memory after-image. 

In my own laboratory some unpublished and not very suc- 
cessful experiments were made to test the relation of attention 
to the visual memory after-image, in the following way.^ We 
had made a number of cards, each card divided into nine com- 
partments, and each compartment having drawn in it a non- 
sense figure of eight lines. The person experimented upon was 
asked to look steadily at the figure on the central compartment 
of the card for thirty seconds, but while she thus held her gaze 
fixed, she was to keep her attention fixed on some other figure, 
for instance, the one in the upper left-hand corner, which was 
of course indirectly and indistinctly seen, but which was to 
occupy the focus of attention for the thirty seconds. At the 
end of that time, the observer closed her eyes, and in pursuance 
of previously given instructions raised her right hand when she 
saw mentally the image of the figure she had looked at, and her 
left hand when the image of the figure she had attended to came 
into her mental vision. These instructions naturally suggested 
an alternation between the two images which very likely would 
not have occurred if no such directions had been given, but it 
seemed to us that if the figure which had been attended to, 
although it had been obscurely seen and the attention had been 
subject to the distraction of remembering not to look at it, 
appeared as a memory after-image for a longer time than did 
the figure merely looked at, we should have evidence that the 
predominant elements in the memory after-image are those 
which were attended to in the original impression. As a matter 
* These experiments were performed by Miss Elvira Kush. 



RECURRENCE OF MOVEMENTS 67 

of fact, the results, obtained from more than twenty observers, 
showed that the figure attended to appeared alone in the mem- 
ory after-image 1.3 times as long as the fixated figure appeared 
alone: some of the observers saw both together for a consid- 
erable part of the time during which the memory after-image 
was observed. It is obvious what the sources of error are here. 
The instructions to be followed during the period of observa- 
tion were difficult, and the observer may have failed in two 
ways to carry them out. On the one hand, attention may have 
wandered to the fixated figure, and on the other, fixation may 
have momentarily shifted to the attended-to figure. The 
question arises whether attention or fixation can better be 
trusted to remain steady, and unless some answer to this ques- 
tion can be found the results of the experiment have little 
meaning. 

Whether or not the predominant elements in the memory 
after-image are always those to which attention was directed 
in the original impression, there is good reason to believe that 
the memory after-image may, like the sense-organ after-image 
and unlike the revived image, contain elements that were un- 
attended to in the original. The very curious experiments of 
Urbantschitsch (141) may be described in this connection. 
From his account of his method of experimenting it is hard to 
make out just how far he was observing the memory after- 
image and how far the object of his study was a revived image, 
but on the whole, since the original object was frequently looked 
at, the process seems to have been essentially a memory after- 
image, or at least to have involved in large measure the activity 
of cortical neurones which had been recently peripherally ex- 
cited. His method was to ask an observer to look at a picture, 
word, or number for a time and then close the eyes. Sometimes, 
he says, the mental image came at once; sometimes only after 
repeatedly looking at the object. After spontaneous changes in 
the image had ceased and it had become stable, various ex- 
ternal stimuli were applied to the observer: tuning-fork tones 
were conducted to his right or left ear, cold or warm applications 



68 MOVEMENT AND MENTAL IMAGERY 

were made to his face, the field of the closed eyes was illumi- 
nated by light flashed from a mirror, and so on. The curious 
effect of these outside excitants was to develop in the memory 
image details that had not been noticed in the original observa- 
tion. But not only could such details be recovered by these, so 
to speak, artificial means : the unnoticed features would some- 
times develop spontaneously in the memory image. Urbant- 
schitsch's most striking results were obtained with pictm-es 
which were covered so that only vague spots of light, shade, 
and color showed through. In the memory image of such an 
object, the experimenter asserts, details of the picture quite 
unknown to the observer would develop, both spontaneously 
and when tones were used as stimuli. -* 

The occurrence in the memory after-image of elements not 
attended to in the original is easily verified by introspection in 
the case of the auditory memory after-image. Ebert and Meu- 
mann (30) called attention to this fact; they point out that 
unlike the image recalled after an interval, the immediately 
recalled auditory image "reproduces all the concrete condi- 
tions of the impression: voice, accent, rhythm, tempo." They 
declare that in this respect it resembles the retinal after-image. 
The auditory memory after-image, as a matter of fact, is prac- 
tically valuable just because it does regularly contain details 
that were unattended to in the original, or even, like the retinal 
after-image, calls our attention to the fact that the original 
stimulation has occurred. This is evident in the case where a 
remark made to us goes unheeded while the sound waves are 
actually operating on the auditory pathways, and only its 
cortical after-effect is responsible for its being finally noticed. 
The necessity, from a practical point of view, of some such 
arrangement is obvious. An object seen can often be looked at 
a second time; the characters not apparent at the first glance 
can be apprehended at the second. But a sound is usually 
fleeting; it is gone beyond recall in a few seconds, and what we 
did not apprehend while it lasted we must be able to catch in 
the memory after-image, or we shall lose it forever. A reason 



RECURRENCE OF MOVEMENTS 69 

will presently be suggested for the superiority of the auditory 
memory after-image in reproducing unattended-to elements. 

Upon the general tendency of any kind of a memory after- 
image to reproduce in some measure details that were not no- 
ticed in the original rests according to Ach (2) the function of 
this process for introspection. We can rely, Ach thinks, on 
having every experience, whatever its nature, left over, as it 
were, in consciousness for examination. The experience itself 
may occur untrammelled by the introspective attitude, and 
then, when it is over, it will spontaneously repeat itself, if at- 
tention is favorable, and may be introspectively studied. Ach's 
experimentation was done by the reaction method, that is, his 
observers were required to respond to the giving of a particular 
signal by making a particular movement. In each experiment 
he distinguishes a fore period, during which the person ex- 
perimented on is waiting for the signal; a principal period, dur- 
ing which the reaction movement is made, and an after period. 
It is this last that is so valuable for introspection. The ideas 
which in the after period the observer has of his experience in 
the earlier periods are to be distinguished, Ach says, from as- 
sociatively produced ideas (what we have called * revived 
ideas ' or * memory images ') both by their clearness and by the 
mode of their origin. It is as though the whole previous ex- 
perience were present at once, and its details may be examined 
as if it were an external object; it may be analyzed without in 
any way interfering with it. Muller (88), on the other hand, 
who has given us an acute study of the sources of error involved 
in introspection and the best way to avoid them, objects to this 
basing of introspection exclusively on the memory after-image, 
for he thinks that, on the one hand, we may to some extent 
examine our experience as it passes, without waiting for an 
after period, and, on the other hand, that the memory after- 
image of an experience is not nearly so completely a reproduc- 
tion of the original as Ach supposes, because, he says, it re- 
produces only what was attended to in the original. 

We have seen that this last statement is certainly not true for 



70 M0\1EMEXT AND IVIENTAL BLiGERY 

the auditory memory after-image at least. Exner (33) is one of 
the psychologists who maintain the existence of an after-effect 
of conscious processes which is not dependent either on con- 
tinued sense-organ excitation or on central excitation. He dis- 
tinguished such an after-effect as a primary memory image. It 
returns, he said, immediately after the withdrawal of the stim- 
ulus; with unattended-to impressions, there is no secondary 
memory image. The latter occurs in the case of an object at- 
tended to for purposes of recall. That is, you have the best 
chance of obser\'ing a primary^ memory image, based purely 
on persistent excitation, in the case of impressions to which 
you did not attend: if you attended to them, you are more 
likely to have a memory image which is based on the associa- 
tive connections set up during the process of attention. Daniels 
(27) in 1894 tried to base experimental observations of the 
primary memory image, or memory after-image, on a similar 
hypothesis. The person experimented on was required to read 
aloud, with entire attention, an interesting story. At a certain 
point in the reading, when his attention was fully occupied, 
the experimenter called out a number of three figures. The 
reader had been prexdously instructed not to stop at this point, 
but to continue reading aloud until the experimenter rapped 
on the table. The rap was given sometimes immediately after 
the figures had been pronounced, sometimes at five, ten, fifteen, 
or twenty seconds afterward. At the rap, the reader paused, 
and tried to recall the numbers that had been pronounced. K 
his attention had been wholly taken up with the reading, he 
had formed no associations which would help him to recall the 
numbers, and only their spontaneous lingering in conscious- 
ness would enable him to do so. \Mien the interval between 
the giving of the numbers and the rap on the table was long, 
the numbers tended of their own accord to recur to the reader's 
mind. E they did not thus spontaneously recur, they could not 
be recalled when the rap came as long as fifteen seconds after 
they had been pronounced, indicating that the memory after- 
image imder these circumstances did not last fifteen seconds. 



RECURRENCE OF MOVEMENTS 71 

Abramowski (1), in a research on the formation of the 
memory image, published in 1909, finds hke Exner a twofold 
source for memory, but the primary memory image, or memory 
after-image, does not in his observations assume the character 
of an image at all. The image, containing distinguishable de- 
tails, is in his opinion wholly a creation of the intellect, that is, 
of the associative processes. The directly persisting effect of 
the original impression is merely a vague feeling, not describ- 
able in language at all, but it is the basis of our recognition 
that we have experienced a thing before. Probably the reason 
why Abramowski came to this conclusion is that he overdid, in 
his experiments, the matter of distraction. He showed his 
observers very complicated * nonsense' designs, with curves, 
dots, crosses, and much variety of color and shading. These 
were presented with different kinds of distractions, given 
sometimes together with the design itself and sometimes im- 
mediately afterward. It is not surprising that under conditions 
of such difficulty even the memory after-image, which, as not 
requiring the formation of any associations, should be reason- 
ably independent of distraction, failed to appear in the form 
of an image. Although these distractions prevented the ob- 
server from reproducing the design he had seen, they did not 
interfere with his recognizing it when confronted with it a sec- 
ond time, from which the experimenter concluded that the 
primary memory process, while it could not appear in the form 
of an image, might be the basis of recognition. But of course 
there must be a limit to the power of a memory after-image 
to reproduce unattended-to details, if we grant that such a 
power exists. Undoubtedly Abramowski's method permitted 
the formation of the visual memory after-image only in so 
vague a state that its function was limited to bringing about 
recognition. 

On the whole, the truth of the matter seems to be that the 
memory after-image, unlike the memory image produced by 
recall after an interval, may contain features that were not 
attended to in the original stimulus. It is very important to 



72 MOVEMENT AND MENTAL IMAGERY 

note, however, that the memory after-image will not appear 
at all unless attention is directed towards it beforehand. It 
does not force itself upon attention. Even in the case where we 
realize that some one has spoken to us, a few seconds after he 
has done so without attracting our attention, there is probably 
some other circumstance that has turned our attention in the 
direction of our companion: it may be doubted whether the 
lingering memory after-image of the sound of his voice ever 
could have * attracted attention' by itself. 

Our motor theory of consciousness, attention, and the image 
can be very simply applied to the explanation of the memory 
after-image and its characteristic difference from the revived 
memory image, with but one additional supposition, namely, 
that a motor centre recently excited tends to renew its excitation 
spontaneously y provided only that incompatible excitations are not 
in progress. Let us suppose that the original stimulus is com- 
plex, and that while certain parts are attended to, others re- 
main unattended to: there is consciousness of them, but only 
vague, marginal consciousness. In terms of our theory, some 
of the motor excitations, receiving a moderate amount of 
inhibition, are giving rise to tentative movements, accom- 
panied by kinsesthetic excitations; while others are getting an 
amount of inhibition that prevents tentative movements : the 
former excitations are the basis of attentive consciousness, the 
latter of inattentive consciousness. Now, the former excita- 
tions, through the kinsesthetic currents they set up, have the 
great advantage that they can not only begin to form move- 
ment systems among themselves, but can enter into move- 
ment systems already formed. Thus, when we look attentively 
at a design with intent to memorize it, we name the various 
parts in it, and the word associations thus called up will easily 
suggest previously formed associative systems of their own. 
Upon the basis of the formation of movement systems and the 
utilizing of old movement systems the recall of details after an 
interval is made possible : hence, only the attended-to parts of 
the impression can be recalled in the memory image. But all 



RECURRENCE OF MOVEMENTS 73 

the motor excitations set up by the complex stimulus, whether 
they involved attention or mere inattentive consciousness, 
have, we may suppose, a tendency to recur after the stimulus 
is withdrawn, and in this recurrent excitation, the antagonistic 
processes that kept certain motor centres from discharge into 
actual tentative movements may have been removed. Thus, 
in the memory after-image details may be attended to that 
were unattended to in the original impression. To put the mat- 
ter very briefly: those elements in the original stimulus which 
were not attended to cannot be recalled after an interval be- 
cause, not producing the proper kinsesthetic excitations, they 
enter into no movement systems, new or old. They can, how- 
ever, like all the other elements in the original, be revived in 
the memory after-image, because a motor centre that has just 
been active is likely to become spontaneously active again, pro- 
vided that incompatible motor excitations are not in progress. 

The fact that auditory memory after-images are less depend- 
ent on attention than visual ones; that is, that a visual memory 
after-image is less likely to contain details unattended to in the 
original than is an auditory memory after-image, I think may 
be explained by the fact that the proper reception of a visual 
stimulus rests so much more on attention than does the proper 
reception of an auditory stimulus. I mean by this that atten- 
tion to a visual stimulus involves much more adaptation of the 
sense organ than attention to an auditory stimulus. An unat- 
tended-to portion of an object seen is often seen with the side 
of the retina and with a lens unaccommodated to its distance; 
thus an unattended-to visual object is often not properly seen 
at all. But the actual impression which an imattended-to aud- 
itory stimulus makes on the ear is not very difiPerent from that 
made by a sound to which attention is given. 

The superiority of the auditory memory after-image to the 
visual is implied by many investigators. Calkins (19) found 
that the most recent of a series of auditory impressions which 
were to be immediately recalled had more advantage on ac- 
count of its recency than the last of a series of visual impres- 



74 MOVEMENT AND MENTAL BIAGERY 

sions similarly recalled: the recent impression must derive its 
advantage in immediate recall from the memory after-image, 
so this result would indicate that the auditory memory after- 
images were clearer than the visual ones. Muller (88) says that 
short intervals between learning and testing verbal material 
lead to an auditory method of learning, because of the tendency 
to use the auditory memory after-image, which he thus implies 
is more striking than the visual memory after-image. 

How long does the memory after-image last? There have been 
attempts to answer this question with regard to the auditory 
memory after-image by the following method. If a series of non- 
sense syllables or numbers is repeated to an observer at a rate 
too rapid to favor the formation of associations between them, 
and he is then asked to recite them *from memory,' he can 
readily do so, in fact they almost recite themselves, provided 
the series is not too long. But there is a sharp and sudden limit 
to the number of syllables that can be thus correctly repro- 
duced. This number has been called the auditory memory span 
of the individual. One of the earliest references to it was made 
by Jacobs (55) in 1887. He regards it as a measure of what he 
calls * prehension,' and notes that in school children the length 
of the span increases with age and is fairly well correlated with 
school rank. Galton (41) appends the statement that it is ex- 
tremely short in idiots. Bourdon (14) in 1894, using numbers, 
letters, and words, also found that the span increases with age, 
especially during the years from eight to fourteen, and that 
after fourteen no progress is made. On the whole, the length 
of the span appeared to be correlated with the teacher's esti- 
mate of the child's intelligence. The correlation with age in the 
normal child is so well established that tests of the auditory 
memory span have been incorporated into the Binet series of 
tests to determine whether a child is mentally as old as his 
physical age. 

Now, theoretically one might suppose that when one comes 
to the limit of his memory span, he reaches the point of time at 
which the first impression of the series has just faded out of the 



RECURRENCE OF MOVEMENTS 75 

memory after-image. Suppose that as many as eight nonsense 
syllables will faithfully repeat themselves in the observer's con- 
sciousness just after he has heard them pronounced. The first 
syllable, then, still exists as a memory after-image. When nine 
syllables are recited to the observer and he fails to reproduce 
them, we should naturally say that the interval of time since he 
heard the first syllable of the series is now so long that the mem- 
ory after-image of the first syllable has disappeared. On this 
supposition it would be a simple matter to measure the duration 
of an auditory memory after-image. But unfortunately it is 
not the first syllable that regularly vanishes first from the mem- 
ory after-image, leaving the rest intact. It may be any syllable, 
or group of syllables, or even the whole series that is gone in a 
flash as soon as the too-extended series has been presented. 

The fact apparently is that some syllables have a longer 
memory after-image than others. In all probability this length 
is determined by the degree of attention given to a syllable in 
the original. The most * striking ' syllables persist longest in the 
memory after-image. As Poppelreuter (112), who makes the 
memory after-image or ' secondary process ' the basis of all the 
higher mental processes, would say, the duration of the second- 
ary process depends on the * consciousness grade' it possesses. 
In terms of our theory, this would mean that the motor proc- 
esses which have involved actual tentative movements pre- 
serve longer their tendency to spontaneous recurrence. To 
this advantage there is added the fact that such motor proc- 
esses may have through their kinsesthetic excitations called 
old movement systems into activity. For instance, out of the 
series of numbers 8 2 714 5 3 the last four numbers may per- 
sist in the memory after-image because they are associated with 
the date of the fall of Constantinople: that is, an associatively 
revived memory image comes to the aid of the true memory 
after-image. 

No satisfactory way of measuring the duration of a memory 
after-image has yet been devised. For, as we have seen, the 
memory span method fails because we cannot take for granted 



76 MOVEMENT AND MENTAL IMAGERY 

that the memory after-images of all the impressions in the series 
will be of equal duration, and it is useless to give an observer a 
single impression and ask him how long the memory after-image 
of that impression lingers in his consciousness. For he is cer- 
tain under these circumstances to make more or less effort to 
recall it by means of associations; thus it will assume, as its 
duration lengthens, more and more the character of a revived 
memory image, its recall based on the connections between 
movements. 

Alexander-Schaefer (4), by the way, showed that the mem- 
ory after-image may be destroyed at its outset by a sudden dis- 
traction occurring immediately after the original impression, if 
that distraction be caused by a source as violent as a pistol- 
shot. He found that the effect of such a noise on the * primary 
memory images * of colors on a rotating drum looked at through 
an opening in a screen was to make the observers * forget * what 
the color was that they had just seen. A less extreme distrac- 
tion, as the work of Daniels showed, does not have this effect, 
at least on the auditory memory after-image. 

Few experiments on the changes undergone by the memory 
after-image during its course have attempted to distinguish 
between this type of image and the revived memory image, 
associatively produced. There are, on our theory, several 
causes which would especially tend to alter the character of 
the memory after-image. The first is the natural tendency of 
a motor excitation, spontaneously recurring after its original 
initiation, to weaken with time; this would produce a fading of 
the memory after-image. Lehmann (58), basing his conclusions 
on the mistaken assumption that one can recognize a standard 
stimulus and distinguish it from others only by comparing it 
with its own image, claimed to have demonstrated the fading 
of the visual memory after-image, or memory image. He 
showed his observers a standard gray disk, and then after an 
interval of five, fifteen, thirty, sixty, or a hundred and twenty 
seconds, he presented either the same disk, or a lighter one, or a 
darker one, the observers being required to recognize the orig- 



RECURRENCE OF MOVEMENTS 77 

inal if it were given. The accuracy of recognition decreased as 
the interval increased, and this Lehmann thought was due to 
the gradual fading of the memory after-image of the standard. 
Later investigators, however, have shown that such compari- 
sons can be carried out without the aid of any sort of image of 
the original standard. 

Wolfe (155), acting on the same assumption of the necessity 
of images for recognition, reported the gradual fading of the 
auditory memory after-image, or memory image. He used tones 
as stimuli, sounding the standard tone, of either 496, 408, 
320, 232, or 144 vibrations, for one second, and then giving a 
second tone, either four, eight, or twelve vibrations different 
from the standard, after an interval varying from one to thirty 
seconds. In a later series eleven different standards were used 
and the effect of longer intervals was investigated. The accur- 
acy of recognition was greatest with an interval of two seconds, 
and from that on diminished as the interval increased. Leh- 
mann noticed a peculiar refreshing of recognition and increase 
of accuracy at a point differing for different observers and ly- 
ing between ten and twenty-five seconds. If this phenomenon 
really depended on a revival of the memory after-image, it 
might have been due to a later recurrence or * perseveration' 
of the image, a phenomenon we shall discuss presently. Whip- 
ple (151) in his study of the auditory memory image gives data 
by which we can distinguish memory after-images from revived 
memory images in his results, though he uses the term * memory 
image' for both. He used five standard tones, of 612, 724, 832, 
928, and 984 vibrations, and after an interval of two, four, six, 
ten, fifteen, twenty, thirty, forty, or sixty seconds, a second tone 
was given, either the same as the first, or eight vibrations 
higher or lower. The presence of an auditory image was in 
many cases evident to introspection: it appeared spontane- 
ously, without any associative supplementing. "Left to it- 
self, it then decreases in intensity and clearness. To offset this, 
the observer has recourse to various memorial aids: he vis- 
ualizes the instrument, contracts his throat, with incipient 



78 MOVEMENT AND MENTAL IMAGEHY 

humming, . . . and exhibits all those muscular phenomena 
which characterize active attention." This is evidently the 
point at which the memory after-image is supplemented by the 
revived image. Despite this supplementing, it will hardly last 
more than a minute. 

Secondly, the generalized motor responses on which the in- 
tensity of the original sensation was based may very naturally 
in their recurrence persist for a time which is less than the dura- 
tion of the recurrent main motor response on which the image, 
itself, was based. This would make the image appear to de- 
crease in intensity, as well as lose its clearness. Whipple, as we 
have just seen, speaks of a loss both in intensity and in clear- 
ness. Merkel (79) reports that the memory after-images of 
noises grow less intense. 

Thirdly, changes in the quality of the memory after-image 
might be produced by the tendency of an unusual movement 
to be supplanted by a more practiced and hence an easier one. 
If two movements, that is, are both complex, and involve cer- 
tain common components, and if one of these complex move- 
ments is of more frequent occurrence than the other, then the 
rarer movement, as it recurs, may easily slip into the commoner 
one, whose synaptic resistances are inherently low. Such a 
tendency on the part of the memory after-image to alter in the 
direction of a more frequent experience is indicated in the re- 
sults of several experimenters: thus Shaw and Warren (143) 
found that when observers were asked to look at a square, and 
then go into another room, and pick out an equal square from 
among ten of different sizes, "for a smaller standard too large a 
square was chosen: for a larger standard too small a square.'* 
Thus, there was a tendency in the direction of a certain middle 
or average size. Leuba (69) found that brightnesses tended in 
a similar way to alter in the direction of a middle or average 
brightness, in experiments which seem to have involved both 
the memory after-image and the revived memory image. We 
shall later see that the true memory image has also this tend- 
ency to be changed into conformity with the most frequent and 



RECURRENCE OF MOVEMENTS 79 

ordinary type of experience. Wolfe, in his experiments on 
tones, reports a tendency on the part of the memory after- 
image to grow lower in pitch, a fact which he explains as due 
to its weakening: "loud tones seem higher than they are, weak 
tones lower than they are." It may be that this was merely an 
illustration of the tendency of the more usual movement to 
supplant the less usual one. Since Wolfe's observers were all 
men, all of the tones he used were of a pitch above what they 
were accustomed to use in the speaking voice, and the tone 
reproductions might have lowered in pitch merely by the ap- 
proximation of their underlying motor processes to habitual 
movements. Whipple's observers, however, were both men and 
women, musical and unmusical; their tendency to flat the image 
appears to have had no connection with either sex or musical 
practice. 

Fourthly, the memory after-image may change its quality 
because the motor process on which it depends is altered by the 
action of other motor processes going on at the same time. 
Movements which are associated in systems with motor excita- 
tions occurring at a given time may tend to supplant the move- 
ments on which a memory after-image is based. Such a process 
of assimilation is common in the case of perception: it is the 
basis of the " proof-reader's illusion," whereby we fail to notice 
a misspelled word. In Bentley's (10) experiments on the com- 
parison of shades of gray, it was found that when the field of 
vision was dark between the showing of the standard gray 
and the comparison gray, the mental image of the standard 
darkened during the interval; when the field of vision was light 
in the interval, the mental image of the standard grew lighter. 
As the research was not directed towards the investigation of 
the influence of the interval, however, the conditions were 
not such that assimilation of the image to the context can be 
said to have been demonstrated. 

It is apparently a further peculiarity of the memory after- 
image that as its first appearance is spontaneous and independ- 
ent of any effort to recall it by association, the mere fact that at- 



80 MOVEMENT AND MENTAL IMAGERY 

tention is not occupied with antagonistic material being enough 
to allow it to arise; so it tends more or less periodically to keep 
on recurring. Lehmann inferred that the auditory memory 
after-image thus recurred at intervals from the fact that the 
percentage of correct recognitions of the standard tone rose 
markedly when an interval of from ten to twenty-five seconds 
intervened between its first and second soundings: the accur- 
acy of recognition was greater with this interval than for shorter 
intervals. A similar rise in the accuracy of recognition was 
found by Whipple, but as recognition does not necessarily im-' 
ply the presence of an image, increase in its accuracy does not 
necessarily imply a renewed image. But the memory after- 
image of an auditory stimulus would naturally appear and 
disappear, for otherwise it would not faithfully represent the 
characteristics of the original, as it does (" it reproduces all the 
concrete conditions of the impression, voice, accent, rhythm, 
tempo"). The original impression is that of a sound having a 
definite beginning and end: the memory after-image then must 
have an end as well as a beginning, and must, to be like its 
original, recur rather than continue. 

The visual memory after-image, reproducing an original that 
is not definitely limited in temporal course, might, one would 
suppose, fade away continuously, without any recurrences. 
Yet it too shows a periodicity. Meakin (76) in the Harvard 
laboratory exposed simultaneously two cards, each carrying a 
different design, between which the observer divided his atten- 
tion impartially for five seconds. The observer then watched 
during the space of one minute the behavior of the memory after- 
images of these two designs. It was found that the two images 
alternated in consciousness. Murray (96) later simplified the 
conditions by presenting one design only, and the persons who 
took part in her experiments reported that the memory image 
of the design appeared "spontaneously at intervals which grew 
longer towards the close of the minute." This periodicity 
strongly suggests the relaxing and recovery of motor processes. 

On the whole, the memory after-image seems to be an experi- 



RECURRENCE OF MOVEMENTS 81 

ence singularly ill adapted to be studied by introspection alone, 
and it is not surprising that Martin (75), whose studies of the 
memory image are based entirely on the introspective method, 
has no use for the term memory after-image. In one form of her 
'projection method,' the observers looked at an object and then 

* called up ' a mental image of the same object alongside of the 
original. This image she thinks is composed of a fleeting posi- 
tive retinal image and a lasting memory image; of a process in- 
termediate between these two and based on the persistent or 
spontaneously recurrent activity of the cortical neurones, she 
finds no trace. Certainly her method would not favor the obser- 
vation of the true memory after-image. She rejects the view 
of Ach that introspection is based on the memory after-image, 
for, she says, such images are too fleeting, and vv^e have no evi- 
dence that anything Uke them occurs in other than visual ex- 
periences. This last is a surprising statement in view of the fact 
that hearing gives us most striking and practically valuable 
instances of the memory after-image, of which we make use 
many times a day. 

The testimony of many psychologists in favor of the exist- 
ence of the memory after-image is to be set over against 
Martin's rejection of it. In Lay's (65) study of mental imagery, 
published in 1898, * memory images' are distinguished from 

* mental images,' and are said to be nearer after-images in their 
character. Goldstein (43), investigating in 1906 the ability of 
normal and abnormal patients to recall a group of objects 
looked at for a brief time, emphasizes the part played by the 
'pure impression,' aside from associative activity: the capacity 
for receiving a pure impression of the objects may stand in in- 
verse ratio to the power of forming associations: the latter is 
valuable in delayed, the former in immediate recall. Rados- 
sawljewitsch (113) also stated that direct recall is a different 
function from delayed recall and may vary independently. In 
Moore's (87) study of the process of abstraction, where the 
observers were shown sets of figures, each set for a very brief 
interval, and required to recognize similar elements in the 



82 MOVEMENT AND MENTAL IMAGERY 

different sets, he says that the figures were held in mind in two 
ways, either by *visuaHzing,' or by * mental analysis*: the 
former would involve chiefly the memory after-image, the latter 
the use of associations. Muller (88) says that the distinctness 
of the visual memory after-image is no guaranty of the per- 
manence of visual ideas based on associations, thus evidently 
recognizing the distinction between the two. 

On our theory, the memory after-image is based on the 
tendency of movements, whether full or tentative, to repeat 
themselves just after they have been performed. To this tend- 
ency there is due an effect of the greatest practical importance. 
Suppose that a series of movements has just been made, and 
that the members of the series are movements that could not 
possibly be performed simultaneously. For example, a series 
of words has just been repeated : of course, no two words could 
be pronounced at the same time. Now, all of these movements 
have a tendency to recur, for a short time at least: but evi- 
dently they cannot actually all recur at once. If one of them 
actually does recur, what shall we say of the state in which the 
motor centres of the others are? Their discharge even in ten- 
tative movements is being hindered by the performance of in- 
compatible reactions, yet they are certainly in a different state 
from that of motor centres which have not recently been ex- 
cited. We may describe this condition of theirs conveniently 
by saying that they have been * set in readiness ' for further dis- 
charge. For example, suppose one is told that when a certain 
signal is given, one is to do either one of two things, the 
acts being incompatible with each other. Each of these al- 
ternatives is attended to in turn; that is, the movements in- 
volved are tentatively performed. If the wait for the signal is 
long, they may be thought of, that is, tentatively performed, 
again, but whether or not they are again thought of, if the 
wait is not too long, both will be in a state of readiness to be 
performed again, although no memory after-images are pres- 
ent to consciousness. 

To the readiness involved in the memory after-image process 



RECURRENCE OF MOVEMENTS 83 

we must ascribe the fact that when two movements are linked 
in a successive system, besides the associative disposition 
whereby the first movement excites the second, there is ap- 
parently formed a reverse association, a weak disposition for 
the second to excite the first. Ebbinghaus (29) found indica- 
tions of this fact, but it was not remarkable that he should do 
so, because in his rough method of experimenting more than 
one syllable was visible at a time. MuUer and Schumann (91) 
gave the matter more careful investigation, and found that 
series of syllables in which the pairs which formed rhythmic 
* feet ' had the order of their syllables reversed, the pairs being 
selected from a number of different series previously learned, 
were learned in a much shorter time than series in which the 
syllables from the original series were presented in wholly ran- 
dom order. When, then, a system is formed consisting of the 
members A — 5, the kinsesthetic excitation from A becoming 
the stimulus for 5, there must be some way in which the excita- 
tion from B also gets a slight power to excite A. The only way 
in which it would appear possible to explain this is to suppose 
that the motor pathway for A, which has just been excited, is 
in a state of readiness to be excited again, and thus actually gets 
some of the kinsesthetic excitation produced by the movement 
B. As Si matter of fact, the readinesses and the actually recur- 
rent excitations on which the memory after-image is based must 
be held responsible for the fact that a successive movement 
system is not a series of events, each of which vanishes utterly 
from the scene as soon as the next one occurs, but a process 
whose parts overlap and hence have some of the characters of 
a simultaneous system. This, as we shall later see, is peculiarly 
true of successive systems that have meaning: the meaning is 
often itself a simultaneous system and helps to give unity to 
the successive system that expresses it. (See pages 141-142.) 
The spontaneous tendency of motor processes to recur, in 
cases where they are not accompanied by imagery, but simply 
by peripherally excited kinsesthetic sensations, is very notice- 
able in many cases. The balancing movements made during a 



84 MOVEMENT AND MENTAL IMAGERY 

few days at sea persist, as every one knows, for a considerable 
time after the stimuli whicli occasioned them have been with- 
drawn. The persistence of organic attitudes is also a frequent 
experience. One jfinds one's self wondering what it was that a 
few minutes ago cheered or depressed one; the organic attitude 
is still there, although the cause of it has disappeared. Again, 
I have often had the experience of being reminded, on rising 
from a chair, to pick up some object that I had laid down by 
the side of it on seating myself, by the recurrence in the muscles 
of my arm of a slight tendency to reach down, the same move- 
ment that I made when I deposited the object. 

Under certain cii-cumstances, the normal tendency of a 
motor process to recur may become exaggerated, so that it 
continues through considerable intervals of time. The students 
of the diseased mind were the first to call this abnormal tend- 
ency by the name ^perseverationy* since its striking manifesta- 
tions are in the morbid recurrence of ideas and impulses in the 
insane mind. Later, psychologists observed it, less strongly 
marked, in normal subjects; for example, Ziehen (162) applied 
the term ' perseveration ' to the disposition, which he observed 
in normal boys from eight to fourteen years of age, to use 
the same reaction word repeatedly in association experiments. 
It was Miiller and Pilzecker (90) who in 1900 erected this tend- 
ency into a fundamental psychological law and connected it 
with the memory after-image. Every idea, they said, has a 
perseverative tendency; that is, it has a tendency, quickly 
diminishing with time, to return to consciousness of its own 
accord. As illustrations of this tendency they quote the rim- 
ning of tunes and phrases *jn the head,' the realization that 
one has misspoken one 's self, the images that float before one's 
eyes in darkness of objects one has been gazing steadily at 
during the day, and the difficulty with which a person breaks 
off one task to take up another. The awareness that one has 
misspoken one's self is clearly a phenomenon of the memory 
after-image. The case of persistent retinal images is a peculiar 
one. The most striking phenomena of this description that I 



RECURRENCE OF MOVEMENTS 85 

have ever experienced were images of microscopic animals that 
seemed to swim in the darkness before my eyes after many 
horn's spent in watching paramecia; images of the weaving in 
and out of scratches on the ice after a day of skating, and images 
of the motion of sm-f , after long watching the waves break over 
the rocks. The last-named images were especially interesting 
because I got them in the field of the open eyes, intermingling 
with the images of objects actually seen. After spending some 
hours in looking at the endless variety of rock-distracted surf, 
I have foimd that on the walk home, the sandy surface of the 
road seemed to glide about before my eyes like the foam at 
which I had previously been gazing. These images all have 
much of the * objectivity ' and relative independence of atten- 
tion that characterizes the retinal after-image, and seem to be 
a kind of cross between a retinal after-image and a perseverat- 
ing memory image: I doubt whether anything corresponding 
to them occurs in other modalities. They remind us of the 
pecuhar position which the retina as a sense organ occupies, in 
being an outgrowth of the brain itself. We may set them 
aside from the other phenomena of perseveration, to await 
explanation from the special student of vision. 

The chief difference between the memory after-image and 
what is ordinarily known as perseveration is one of degree. 
Every process has a tendency to recur immediately after its 
first occurrence. Under some circumstances this tendency is 
exaggerated so that the process recurs again and again. Its 
first occurrence is probably never normally due to persevera- 
tion, but rather to the effect of an outside stimulus or to ordi- 
nary associative processes: that is, it is doubtful whether in a 
normal brain at least any process can spontaneously recur if 
a considerable interval has elapsed since its previous occur- 
rence. When a tune runs in my head, as tunes invariably do, 
for like Professor Titchener (137, page 9) " I never sit down 
to read a book, or to write a paragraph, or to think out a prob- 
lem, without a musical accompaniment," I can almost always 
trace the particular tune to some suggestion from within or 



86 MOVEMENT AND MENTAL IMAGERY 

without : the spontaneous feature of it is not its first occurrence 
to my mind, but the fact that after it has been suggested it 
keeps on uninterruptedly. That which distinguishes a per- 
severating process from any other process is apparently an 
abnormal duration of the tendency to recur. It may, indeed, 
be true that all the recurrences of a perseverating process are 
associatively suggested; for example, that not only the first 
recall of the tune is due to some suggestion, but each of the later 
recurrences of it as it runs in my head. For instance, it may be 
some rhythmic process like my breathing or heart-beat that 
keeps recalling the tune. As a matter of fact, at one time I 
made a record of my perseverating tunes and the conditions 
under which they appeared and disappeared, and found in- 
dications that a particular tune could be banished by the 
performance of some unrhythmic activity on my part, such as 
writing a letter. But in any case, even if each recurrence of a 
conscious process later than its first recurrence is due to an 
associative suggestion, there must be an unusual degree of read- 
iness to be excited on the part of the perseverating process, or so 
very slight an associative current would not be sufficient to re- 
vive it. 

The tendency to exaggerated recurrence or perseveration is 
greater in fatigue and in the case of abnormal minds. It is also 
found in association experiments where some emotionally dis- 
turbing suggestion has been made: the observer is apt to have 
recourse to some previously used reaction word or stimulus 
word when he is * upset' a little by the new stimulus word. All 
these facts indicate that when there is interference with the 
free onward course of associative activity the tendency is for 
recently excited processes to recur. It is easier for some reason 
to repeat an old reaction than to perform a new one. When 
young children are made the subjects of association experi- 
ments, they show a tendency for the same reaction word to 
perseverate, because the smallness of their vocabularies makes 
it hard to recall new words. Khythmic processes are especially 
likely to perseverate in states of fatigue, for rhythm, itself 



RECURRENCE OF MOVEMENTS 87 

involving constant repetition of the same motor response, is 
especially a path of least resistance when fatigue has diminished 
the body's energies. 

An individual who shows strong perseverative tendencies 
in association experiments is by no means necessarily a person 
who will show peculiar persistence in working out a problem. 
The perseveration of simple movement systems is no guarantee 
that very complex systems will have the same tendency. 
Lankes (67) has recently studied the correlation of persevera- 
tive tendencies shown in various laboratory experiments with 
estimates of the character of the observers for persistence in 
their work; the correlation, one might say, between persevera- 
tion and perseverance. It turned out to be slightly negative. 
He is inclined to explain this fact by supposing that persevera- 
tion is a native quality, while perseverance *'is the result not 
of nature and the native system alone, but of that and the 
individual's own effort and will." In the chapter on the prob- 
lem idea we shall try to get further light on this subject. Per- 
sistence in the performance of a task, we shall maintain, is due 
to persistence and perseveration of an activity attitude. The 
worst enemy of the activity attitude is fatigue, and since ordi- 
nary perseveration, involving the recurrence of small movement 
systems, is stronger in fatigue, the relatively more fatigable 
individuals who display it would be expected to show less per- 
sistence of the activity attitude and less perseverance in the 
solving of a complex task. 



CHAPTER VI 

THE connectiis;g links in movement systems: 

ASSOCIATIVE dispositions 

The motor theory we have been working out assumes, on 
what seem good grounds, that when an 'association of ideas' 
is formed, — as, for instance, the association between the face 
of a person and his name, — the real connection in the brain 
is made between the sensory pathway excited by the perform- 
ance of a movement in response to the first stimulus, the face, 
and the motor pathway which evokes a movement in connection 
with the second stimulus, the name. It is the movements that 
are made, fully or tentatively, in connection with the percep- 
tion of the person's face, which by the kinsesthetic excitations 
they occasion get the power to produce the movements in- 
volved in the recall of his name. All association is the associa- 
tion of movements. It has been customary to speak of the proc- 
ess of learning, when it involves the recall of ideas, as resting 
on the formation of associative dispositions or tendencies. The 
non-motor theory of association supposes that when two sen- 
sory centres are simultaneously excited, resistances are lowered 
along a nervous pathway connecting them; thus, an associative 
disposition or tendency is formed between them, on the basis 
of which the later excitation of one is likely to spread to the 
other and produce recall of an image of the stimulus which 
formerly acted on the other. Our theory, on the other hand, 
makes the associative disposition consist of lowered resistances 
between the kinsesthetic pathway involved in the performance 
of one movement and the motor pathway involved in the per- 
formance of another. 

We have now to consider some of the laws which govern the 
strength of associative dispositions, thus understood. This 
chapter will be divided into four sections : the first dealing with 



LINKS IN MOVEMENT SYSTEMS 89 

methods by which the strength of associative dispositions may 
be measured; the second, with the effect of repetition on as- 
sociative dispositions; the third, with the effect of time upon 
them; and the fourth, with their effect on each other when 
called successively into play. 

I. Measures of the Strength of Associative Dispositions 

Evidently the first thing we need, in investigating the causes 
which strengthen and weaken associative dispositions, the 
connecting links between the members of movement systems, is 
some means of measuring the strength of these connections. 
The effects of their varying degrees of strength we constantly 
feel in ordinary life: there are facts that we have at our tongues' 
end, and can never forget, as I can never forget the list of coun- 
ties in New York State, which I learned as a schoolgirl; and 
there are facts that seem to have vanished beyond hope of re- 
call; as when, for example, we return to a place we have once 
visited, and, far from recollecting the circumstances of the 
former visit, we say that the place does not even look familiar. 
But the exact measurement of these degrees of strength can 
be carried out only in the laboratory, and under somewhat 
artificial conditions. 

To begin with, we must note that an associative disposition 
may be too weak fully to excite the motor centre concerned, 
and yet be of influence in other ways. For example, I may have 
once formed associative dispositions between the words 'fall of 
Constantinople' and *1453.' At a later time, I may be asked 
when Constantinople fell, and the kinsesthetic excitations from 
the movements involved in pronouncing or attending to these 
words may be unable to set into activity the movements in- 
volved in pronouncing the date. I have * forgotten' the date: 
the associative dispositions have weakened too far to produce 
recall. Yet if some one says, * Was it in 1456.^' I answer, *No; 
that does not sound right'; and if the date 1453 is suggested, I 
know at once that it is correct. So the associative dispositions 
cannot have vanished altogether. Associative dispositions that 



90 MOVEMENT AND MENTAL IMAGERY 

are too weak to produce actual recall may be termed * subliminal 
dispositions.' The name is not supremely well chosen, for it 
implies the sense of dispositions that function below the level 
of consciousness, and very strong associative dispositions may 
do this precisely because they are so strong. If a disposition is 
so strong or so unopposed that there is no delay in its function- 
ing, it has no conscious accompaniment : the things we are fully 
accustomed to do we can do with attention elsewhere. How- 
ever, for want of a better word we may use 'subliminal' for 
those dispositions which are too weak to produce recall, and 
term those which, because of their strength, function with little 
or no conscious accompaniment, 'automatic dispositions.' 

If an associative disposition is supraliminal, that is, strong 
enough to produce actual recall, an obvious way to measure its 
strength would be to measure the time it takes to e;ffect the recall. 
If we can give the date of an historical event instantly when we 
are asked for it, we feel that the associative disposition is stronger 
than is the case when we hesitate. It was Francis Galton (40), 
that man of suggestive ideas, to whom there first occurred, in 
1879, the thought of measuring the time occupied by associative 
processes. He noted, with the aid of *'a small chronograph," 
the time required for a word, which he looked at, to suggest 
"about a couple of ideas" to his mind, and found that with 
seventy-five stimulus words, "it took a total time of 660 sec- 
onds to form the 505 ideas " that occurred to him. He had no 
intention of measuring the comparative speed of different in- 
stances of association, however. Four years later, Trautscholdt 
(140) in Wundt's laboratory undertook to measure accurately 
the time required for one mental process to call up another by 
association. He used a Hipp chronoscope and finger keys, the 
experimenter pressing one as he called out a stimulus word, and 
the observer pressing another as soon as an associated word was 
suggested. With the simple conception which then prevailed of 
the processes involved in such reaction experiments, he thought 
that the actual time occupied by the functioning of the asso- 
ciative disposition in recall could be obtained by finding, in 



LINKS IN MOVEMENT SYSTEMS 91 

another series of experiments, the average time taken by the 
observer for the mere recognition of words pronounced to him, 
and subtracting this * recognition time ' from the total time 
occupied in the association reaction. We now reahze that the 
processes which occur, when an experiment involving the meas- 
urement of the time of an association is performed, do not con- 
sist simply of the addition of an act of association to an act of 
recognition. If the observer has been instructed before the 
stimulus word is given that he must let it suggest an association 
to him and must press a key as soon as it has done so, his whole 
experience, from the receiving of the instructions on, will be 
quite different from what it would have been if he had been told 
at the outset that he was required merely to recognize the 
stimulus word. We must abandon, then, the hope of measuring 
the time taken by the associative process proper, the passage of 
the nervous current from one cortical region to another. Since, 
however, although the time required for other processes than 
association itself must always be included in the total time of 
an association reaction, these processes, if the conditions are 
properly arranged, may be considered as constant factors; since 
the time required to recognize the stimulus word and to make 
a reacting movement may be treated as constant if a sufficiently 
large number of experiments is made, we can regard marked 
differences in the total association reaction time as due to dif- 
ferences in the association process. Cordes (23) has raised the 
objection that all time measurements of this process are faulty, 
because it is impossible for the observer to make the reacting 
movement, whether it be the pronouncing of an associated 
word or the pressing of a key, at the exact instant when the 
mental process of association is complete. There is evidently 
truth in this statement, yet practice will enable an observer to 
fall into a regular habit with regard to the instant in the process 
at which he makes his reaction, so that the effect on his asso- 
ciation time of various alterations in the conditions may be 
safely studied. For this and other reasons, however, it is not 
safe to draw conclusions regarding the peculiarities of the asso- 



92 MOVEMENT AND MENTAL IMAGERY 

ciative processes in different observers from differences in their 
average reaction times. 

Later investigators have substituted various reJinements in 
the way of Kp keys and electrical devices for recording the time 
of stimulation, in place of Trautscholdt's finger keys, but as a 
matter of fact, the differences in association reaction time under 
different conditions are so marked that a simple stop-watch, in 
the hands of a practiced experimenter, will suflfice for measure- 
ment purposes. 

The evidence that the reaction time of an association is 
shorter, the stronger the associative disposition, is conclusive. 
In the first place, the reaction time required for a stimulus word 
to call up a given reaction word is shortened by new repetitions. 
This was found by Muller and Pilzecker (90). In the second 
place, since we know that associative tendencies may weaken 
and be almost entirely obliterated with time, the fact that the 
association reaction time is longer, the greater the age of the 
association, is a further indication that this time is a fair meas- 
ure of association strength. Another piece of evidence is the 
following. Muller and Schumann (91) showed that when a 
series of nonsense syllables is learned, associations are formed 
not only between the first and second syllable of each pair, 
but also between the second syllable and the first; that is, in the 
backward direction. They proved this by demonstrating that 
fewer repetitions were needed to relearn a series in which the 
order of the syllables in the pairs was reversed than one in which 
the syllables were given an entirely new order. The results 
show, however, as we should expect, that the number required 
for the * reversed' relearning was greater than that required for 
relearning the unaltered original series; that is, the backward 
associative tendencies are weaker than the forward ones. In 
harmony with this Muller and Pilzecker found that the asso- 
ciation time when the first member of an associated pair calls 
up the second is shorter than when the second calls up the first. 
Finally, the fact that association time varies along with certain 
other measures of association strength, which we shall mention 



LINKS IN MOVEMENT SYSTEMS 93 

presently, deepens the conviction that the speed with which 
an associative disposition acts is a good measure of its strength. 
There are limitations, however, to its usefulness: evidently 
there will be a maximum speed beyond which it will be im- 
possible to go, but beyond which association strength may still 
increase. Two recalls might both be made so rapidly that no 
chronoscope could record the time of the process, and yet their 
associative dispositions might not be equal in strength. 

It is worth noting that the association time of a wrong asso- 
ciation is on the average longer than that of a right association. 
A wrong association, that is, a case where the observer gives 
as the associate of a certain stimulus word or syllable one that 
was not associated with it in the original series, must, of course, 
rest on some other associative connection with the stimulus, or 
it may be a perseveration, based only to a very slight degree on 
associative connections. In any case, the tendency which gives 
rise to the wrong response is evidently the strongest tendency 
on the field at the time, and one would think that in series which 
have been very imperfectly learned, the wrong tendencies 
might be as strong as the right ones, so that the mistakes might 
be made with as much promptness in the wrong cases as the 
correct syllables in the right cases. But the tendency which 
leads to a mistaken association, though it may be the strongest 
one on the field, can never be very strong, otherwise the wrong 
syllable would be presented along with enough general asso- 
ciative energy to cause it to be immediately recognized as 
wrong. 

The stronger an associative tendency, then, the more rapidly 
it works, up to a certain limit. Further, the stronger a tend- 
ency, the longer it will last. This is, of course, not a self-evident 
statement. But it is supported by several facts: on the one 
hand, it has been found that, the more repetitions given to 
material that is to be learned, the longer it will be remembered. 
Also, those associative tendencies whose reaction times are 
shortest are those which remain above the limen longest 
(Miiller and Pilzecker, 90). The strength of a supraliminal 



94 MOVEMENT AND MENTAL IMAGERY 

associative tendency can then be measured by the length of 
time during which it remains suprahminal. Perseveration, or 
the apparently spontaneous tendency of certain ideas to recur 
to the mind, to *run in the head,' would of course be a cooperat- 
ing factor here. Pappenheim (103) gave his observers a hun- 
dred stimulus words, to which they were asked to respond by 
speaking the first word they thought of; at the close of the 
series he repeated it immediately, and counted the number of 
cases in which the same reaction was made to a given stimulus. 
These cases proved to have shorter reaction times than those 
where a different reaction was made, indicating that they were 
based on stronger associative tendencies. It has also been found 
to be true that if a given reaction word is used by a number of 
different observers in response to a particular stimulus word, — 
as, for example, * mother' in response to 'father,' — the reac- 
tion times of these preferred associations are unusually short, 
indicating that the stronger an associative tendency, the more 
likelihood there is that it will be common to many minds (140). 
It would hardly be feasible, however, to measure the strength 
of an associative disposition by finding out how many people 
possess it. 

Still another way in which the strength of a supraliminal dis- 
position may be measured is by finding how much resistance it 
offers to the formation and operation of a new disposition. Sup- 
pose that a given word or syllable, A, has been associated with 
another one, B, and that one desires to measure the strength of 
the association at a given time. Let A now be presented a cer- 
tain number of times with another word or syllable, C, and 
then let A be given as a stimulus word. How many repetitions 
of the experience A-C will be necessary before A will suggest C 
more readily than it suggests B ? The number will evidently be 
greater, the stronger the disposition A-B. Experiments of this 
sort were tried by MuUer and Pilzecker (90), who used the 
term * effectual inhibition' to designate the tendency which the 
second disposition, A-Cy would have to prevent the working of 
the earlier disposition, A-B, and the term 'generative inhibi- 



LINKS IN MOVEMENT SYSTEMS 95 

tion' to designate the tendency which the previous existence 
of the disposition A-B would have to prevent the formation of 
the disposition A-C at all. They did not, however, attempt to 
measure the strength of A-B by the number of repetitions re- 
quired to make A-C effective, but limited themselves to show- 
ing that an ejffectual inhibition did occur. Ach (3) used a 
similar method for solving a different problem: his observers 
were instructed to resist a tendency to give the reaction to 
which a certain stimulus word would naturally lead on the 
basis of certain previously formed associative dispositions, and 
to give a diJfferent reaction of a kind described in the instruc- 
tions furnished at the outset. He then measured the strength 
of the effect of these instructions by the number of repetitions 
that had been used in the formation of the associative disposi- 
tion that was successfully resisted. For example, in a given 
series a certain syllable occurs immediately before a certain 
other syllable: this series is repeated a given number of times. 
The observer is then presented with the first syllable as a 
stimulus, after having been instructed on no account to react 
by giving the second syllable, but instead to give a syllable 
that rhymes with the stimulus syllable. If he succeeds in doing 
this, the number of repetitions of the original series forms a 
measure of the effect of the instructions upon his mind. 

Finally, an a priori estimate of the strength of a disposition 
may be roughly made by referring back to the number of repe- 
titions used to found it. If equal times elapse between the found- 
ing of two associations and their functioning, then that one may 
be assumed to be the stronger in whose establishment more rep- 
etitions were used. 

We may now turn from supraliminal dispositions to sub- 
liminal ones, and ask how it is possible to measure the strength 
of dispositions that are too weak to produce recall. The only 
satisfactory method of doing so is the so-called ' Saving Method,' 
where the effect of previous learning is measured by the saving 
of time in relearning. Let us suppose that in childhood a person 
learned a poem to recite at a school * exhibition.* At the pres- 



96 MOVEMENT AND MENTAL EMAGERY 

ent time he can recall of that poem just nothing at all, not even 
the title. But suppose that he is set to learn it now, in company 
with a person of equal learning capacity to whom it is entirely 
new. If account is taken of the time the two individuals take 
to learn the poem, and the number of times each has to read it, 
the person who has learned it before will probably be found to 
have a distinct advantage. The old associative dispositions that 
are too weak to produce recall are yet existent, and it is easier 
for the new repetitions to strengthen them than for wholly new 
associative dispositions to be formed. 

Ebbinghaus (29) used this method in his pioneer experiments 
on memory, in which he was his own observer and learned a 
remarkable number of nonsense syllables. The method in de- 
tail was as follows. Say that a series of twelve nonsense syllables 
is to be learned, and that after a certain number of repetitions 
eight of the syllables can be correctly given; say, the first five 
and the last three. The associative dispositions connecting the 
fifth with the sixth, the sixth with the seventh, the seventh with 
the eighth, and the eighth with the ninth are then too weak to 
function in actual recall. It does not follow that they are all of 
equal strength. Suppose that the entire series is read through 
again, and that the ninth syllable can now be given correctly. 
Since only one new experience was needed to bring it above the 
limen, it would appear to have been the strongest of the four 
subliminal tendencies. In like manner we can find the com- 
parative strength of the other three by determining how many 
repetitions of the series are needed to produce recall of the cor- 
rect syllables. Thus it can be determined what position in the 
series of syllables, the beginning, middle, or end, is most favor- 
able to the quick forming of associative dispositions. Further, 
we may wish to measure, not the strength of dispositions that 
are subliminal because the learning process has not gone far 
enough, but that of dispositions which, originally strong enough 
to function in recall, have become subliminal with the lapse of 
time. Twenty-four hours after the first learning, some disposi- 
tions will have fallen below the limen of effectiveness for recall. 



LINKS IN MOVEMENT SYSTEMS 97 

Their strength can be measured by finding the number of new 
repetitions needed to restore their power of recall. Thus we 
have a means of determining the speed with which associative 
tendencies fall off with time. If tests are being made of the ef- 
fectiveness of different methods of memorizing, then we need 
a value which will represent the average strength or permanence 
of the associative tendencies in a given series of nonsense syl- 
lables. Such a value may be obtained, even for a series all of 
whose members are either still below the Umen of reproduction 
or have dropped below it with time, by noting the number 
of repetitions necessary to bring the whole series above the 
limen; that is, to produce a perfect recitation of the series. If 
it is the representative association strength of the whole series 
after an interval that is wanted, evidently we ought to take 
into account the difficulty of originally learning the series. If 
it takes six repetitions to relearn one series of syllables, and 
only four repetitions to relearn another, it would not be fair to 
conclude that the associative tendencies of the first series have 
decayed more rapidly with time than those of the second, for 
the first series may be a harder series in itself. The ratio of the 
number of repetitions needed to relearn the series, to the num- 
ber that were originally needed to learn it, is what we need to 
find; or the percentage of repetitions that are saved in the relearn- 
ing. This latter value was the one used by Ebbinghaus and 
the method of finding it has been termed the * Saving Method.' 

A subliminal association, then, may have its strength meas- 
ured by the number of repetitions needed to bring it above the 
limen. This measurement, of course, assumes that the value of 
the repetitions is always the same in cases where the numbers are 
compared. Evidently the conditions under which the repetitions 
occur must be carefully controlled, and in particular, the group- 
ing or distribution of the repetitions must be taken into ac- 
count. 

While subliminal associative dispositions obviously cannot 
have measured the speed with which they function in recall, 
some interest does attach to the quickness with which one 



98 MOVEMENT AND MENTAL IMAGERY 

recognizes that an associative disposition is subliminal; the 
promptness, that is, with which a learner acknowledges failure 
in the effort to recall. In experiments, for instance, where non- 
sense syllables have been learned in pairs and the time is meas- 
iu*ed which is necessary for the first syllable of each pair to 
recall the second, the *zero cases* have also had their times 
recorded. *Zero cases ' are cases where the observer ends by say- 
ing, *I give it up,* or words to that effect. Can anything re- 
garding the strength of subliminal dispositions be inferred from 
these zero times .^ If you decide promptly that you have for- 
gotten the associated syllable, does this mean that the sub- 
liminal associative tendencies, which are undoubtedly there, 
and might be revealed by the * Saving Method,' are weaker than 
in the cases where you spend a few seconds in a vain effort to 
recall.'^ Miiller and Pilzecker say that the association time for 
zero cases is longer, the better known the series; that is, it in- 
creases with the number of repetitions. This seems natural : in 
a better-known series the associations that are too weak to 
produce recall would be only a little below the threshold, and 
introspection often distinguishes faithfully between something 
that we can almost recall and something that is hopelessly gone. 
If the observer feels, with right, that the missing syllable is on 
the tip of his tongue, he is apt to take longer before deciding 
to give the matter up as hopeless. Ephrussi (32) also, who was 
comparing the effectiveness, for learning pairs of nonsense syl- 
lables, of repeating each pair a number of times in succession 
and of reading the whole series of pairs through an equal num- 
ber of times, found that while the former method gave more 
right associates and shorter reaction times, the times of its zero 
cases were longer, another proof that a slow zero reaction 
means stronger subliminal tendencies. 

Besides making relearning easier, subliminal associative dis- 
positions may betray their influence in making it easier to per- 
ceive and to recognize objects. If the motor pathways for the 
tentative movements which are involved in attention to a given 
object are excited by kinsesthetic influences so weak that no 



LINKS IN MOVEMENT SYSTEMS 99 

actual movement, even tentative, results, they are nevertheless 
set in readiness, apparently, so that subsequent attention to 
and recognition of the object take place with more speed. Un- 
fortunately, there has not yet been devised any satisfactory 
way of using tliis fact to measure the strength of subliminal 
dispositions. 

The effect of such dispositions on perception was studied by 
Ohms (100). He employed series of pairs of German and Rus- 
sian words. These were presented to the observer a certain 
number of times. The number of repetitions was chosen so that 
the majority of the associative tendencies should be below the 
limen after an interval of twenty-four hours : that is, the person 
experimented on, when shown a Russian word, could not recall 
the German word that had accompanied it. The subliminal 
associations which nevertheless existed were tested in the fol- 
lowing way. Two six-pair series had been used on the preceding 
day. There were now shown eighteen Russian words in suc- 
cession, the time of exposure for each being so short that the 
word could not, ordinarily, be correctly read. In the final form 
of the method, a German word was allowed to be read before 
each of the Russian words was shown. In six out of the eighteen 
cases, the German word preceding was the one which had in 
the preliminary experiments been associated with the Russian 
word shown. In six, the German word had had no previous 
association with the Russian word, but the latter had been used 
in the preliminary experiments. And in the other six, an en- 
tirely new Russian word was shown. Thus the effect of the 
associative dispositions connecting the German and Russian 
words shown in the preliminary experiments, which were not 
strong enough to enable the observer to recall the Russian 
word when its German companion was pronounced, was ex- 
p>ected to show itself in producing readier and more accurate 
reading of those Russian words which were preceded, in the 
test, by their proper German associates. Evidently, there were 
two ways in which the subliminal tendencies might function: 
they might influence the time taken to read the Russian words, 



100 MOVEMENT AND MENTAL IMAGERY 

and they might influence the correctness with which the Russian 
words were read. The times required for reading were meas- 
ured electrically, with a Hipp chronoscope and lip key. In a 
later series the person experimented on had to listen to the 
Russian words instead of looking at them, and the necessary 
indistinctness was admirably secured by the use of an old- 
fashioned telephone receiver. The results showed in both series 
that the Russian words were more correctly recognized when 
they were preceded by their originally associated German 
words; that is, when subliminal associations cooperated with 
the faint visual or auditory impression of the Russian word. 
On the other hand, the influence of these associative tendencies 
on the speed of recognition was less definite. There seemed, 
in fact, to be two types of observers : in one the recognition was 
quicker when the subliminal tendencies were working; in the 
other it was quicker when they were not. Ohms says that the 
former class of observers comprises those in whom the motor 
tendency — that is, the tendency to pronounce the words — was 
strongest. It is not clear just what this would have to do with 
the case. One would conjecture, rather, that the difference 
between the two types of observers may have depended on 
whether they did or did not make an effort to recall the Rus- 
sian word in the interval before it was presented and after the 
German word had been given in the test series. Suppose that 
the German word given in the test, as a preliminary to a Rus- 
sian word, was recognized to be one that occurred in the learning 
series. For some observers it might start, in the interval before 
the Russian word came, a tendency to wonder what the associ- 
ated Russian word had been, and when the word was presented, 
a second or two of criticism might precede its being accepted. 
On the other hand, if the observer did not recognize the Ger- 
man word as having occurred in the preliminary series, he 
would simply make a stab at the Russian word without troub- 
ling to criticize his identification of it, and his reaction times 
would be shorter in those cases where the preceding word was 
unassociated. The second type of observer might make no 



LINKS IN MOVEMENT SYSTEMS 101 

effort, on having the German word presented, to recall its Rus- 
sian companion, but might simply give, as soon as he saw or 
heard the Russian word, his best interpretation of it. In this 
case, where the working of the liminal associations is not inter- 
fered with by the effort to make them supraliminal, they might 
do good service in actually shortening the reaction time. In 
such a case only could the time required for a correct reading of 
the Russian word be regarded as a measure of the strength of 
the subliminal tendencies. As the results of Ohms stand, the 
only actual measure of this quantity which they furnish is the 
number of correctly read elements in the Russian words. 
Evidently one important source of error here would lie in the 
fact that the sounds or printed characters in one word might 
be intrinsically easier to recognize than those in another. In 
the part of the investigation where the words were spoken into 
the telephone, account was taken of this factor. Gutzmann 
had previously pubhshed a work showing experimentally which 
consonantal sounds are hardest to recognize, and care was 
used in forming the series to distribute these difficult conson- 
ants judiciously throughout. In the series with visual presenta- 
tion no such precautions were taken. On the whole, the work 
gives rather evidence that subliminal tendencies do influence 
the perception of objects under these conditions, than a quanti- 
tative measure of the strength of such tendencies. 

The effect of subliminal associative dispositions on recogni- 
tion was demonstrated in the experiments of Reuther (115). 
Every one knows that long after an object has been forgotten, 
in the sense that one could not recall a memory image of it, it 
can still be recognized when it is actually presented. Evidently 
subliminal associative dispositions betray their existence in 
bringing about recognition of an object as having been met be- 
fore. This effect was studied by Reuther, using a method which 
he called that of 'Identical Series.* Series of four-place numbers 
were presented to the observer a certain number of times. Then 
a series was presented, concerning which the observer was told 
that each of its members might be either identical with a mem- 



102 MOVEMENT AND MENTAL IMAGERY 

ber of the preceding series, or entirely new: the observer must 
decide which. As a matter of fact, these instructions were de- 
ceptive: the second series was exactly like the first, both as 
regards its members and their order. Reuther calculated the 
ratio of the number of members correctly recognized as old to 
the total number of members. This value evidently represented 
supraliminal as well as subliminal associative tendencies. 
Sometimes, when an observer correctly recognized a member of 
the series as old, he would be able, by virtue of supraliminal 
dispositions, to anticipate the next: sometimes he would sim- 
ply be able, by virtue of subliminal dispositions, to recognize 
the next member when it came. The introspections of the 
observers could be appealed to in order to separate these two 
classes of cases; but the method furnishes no way of measuring 
the strength of the subliminal dispositions whose existence is 
thus indicated. 

Another method of testing tlie effect of subliminal disposi- 
tions on recognition was that of Fischer (37). Here the ob- 
server read a series of nonsense syllables a given number of 
times. Five seconds after the last reading he tried to recite the 
series. If he gave a wrong syllable the experimenter corrected 
him. But if he was at a loss for a syllable, then the experi- 
menter suggested one which might be either right or wrong; it 
remained for the observer to decide which. While subliminal 
dispositions must be influential in such a decision, there seems 
no way of measuring their strength. Nor does the * Recon- 
struction Method,' as it is called by Gamble (42), serve this 
purpose any better. It was first used by Bigham (12) in 1894. 
It consists in presenting the material to be memorized in a 
definite order, and then, after a certain number of repetitions 
and a certain interval, presenting the members of the series 
simultaneously, with the order abohshed, and requiring the 
observer to reconstruct the series by rearranging the members. 
Thus a series of nonsense syllables may be read to the observer, 
a certain number of times. Then, after an interval, he is given 
a pack of cards each bearing one of the syllables, and spreading 



LINKS IN MOVEMENT SYSTEMS 103 

out the pack before him he attempts to reconstruct the original 
order of the series. This method was used by Bigham for num- 
bers, colors, and forms only; when words and syllables were the 
material, the observer was obliged to reproduce the whole 
series by writing it out, instead of being supplied with the mem- 
bers in altered order. Gamble used smells, nonsense syllables, 
and "Bradley colored papers" two inches square. 

The process of reconstructing the order of a series when the 
members are supplied is in its psychic aspect rather compli- 
cated. In the first place, it probably involves association of a 
given member with its absolute position in the series. The ob- 
server, turning his attention to a particular syllable, would say 
to himself, "This was in the first half of the series," for in- 
stance. He would be practically certain to make such an as- 
sociation in connection with the first and last members of 
the series. We shall later consider just what is involved in the 
association of a member with its position as early or late in the 
series. Apparently it may occur without the operation of any 
supraliminal association of the member in question with other 
members of the series. One can be quite sure that a syllable 
belonged in the first part of the series without being able to 
reproduce a single other syllable. Besides associations with 
absolute position, supraliminal associations between members 
might also play a part in the rearranging. On looking at a cer- 
tain syllable, one might recall the one that came next to it, and 
after picking the recalled syllable out of the pile, reconstruct 
the sequence. Finally, subliminal associations might help. That 
is, when one looked at a certain syllable, one might be quite un- 
able to remember what came next. But glancing over the other 
members, one might recognize the syllable required, as soon as 
one's glance lighted on it, and this recognition would occur 
through the associative tendencies which had been too weak to 
bring about recall. But the Method of Reconstruction, like 
those just previously discussed, does not offer any way of dis- 
tinguishing between the cases where the associations concerned 
were subliminal and those where they actually functioned in 



104 MOVEMENT AND MENTAL IMAGERY 

recall; hence, it cannot be used as a measure of the strength of 
subliminal associations. We may sum up the subject of such 
measurements by saying that the only satisfactory method is 
that which estimates the strength of a subliminal tendency by 
the number of repetitions necessary to bring it above the 
threshold; that is, the Saving Method. The functioning of such 
tendencies in recognition has never been satisfactorily meas- 
ured. A further advantage of measurement by the new rep- 
etitions required is that it can be used for tendencies which 
are so weak that they could not produce any effect even on 
recognition. For the associative link between two experiences 
may have so far degenerated that it will not even make us rec- 
ognize the second experience as familiar, and yet it may effect 
a saving in the number of repetitions needed to relearn the 
series. 

II. The Effect of Repetition 

An associative disposition is founded between two move- 
ments when the kinsesthetic excitation started by one move- 
ment coincides with the innervation of the other movement: 
the kinsesthetic stimulus energy then finds its way into the 
motor pathway belonging to the second movement, and the 
resistances along the path which leads from the kinsesthetic 
pathway of movement A to the motor pathway of movement 
B are lowered. Each time that movement A precedes or accom- 
panies movement B, the resistances are lowered a little more, 
until movement A comes through its kinsesthetic excitations 
to furnish a sufficient stimulus to movement B. Thus, each 
repetition of the two movements in conjunction strengthens 
the movement system that is in process of formation. 

Does each repetition do an equal amount towards lowering 
resistances and strengthening the movement system .^^ The 
principal influence at work here is the amount of attention 
accompanying the repetition. 

Just what on our theory is the difference between a repetition 
with attention and a repetition without attention.? The essen- 



LINKS IN MOVEMENT SYSTEMS 105 

tial feature of attention we have assumed to be the occurrence 
of tentative movements belonging especially to the stimulus 
attended to. Take the case of a series of nonsense syllables 
which is presented visually. Reading it to one's self without 
attention may mean neglecting to make even tentatively the 
movements involved in pronouncing it : in such a case the most 
important kinsesthetic currents needed to establish a move- 
ment system will be lacking. The same thing will be true if the 
syllables are read aloud to the observer: if he does not listen 
with attention, he will not be making the tentative movements 
that are necessary to the establishment of the associative dis- 
positions. If, on the other hand, the observer has to read aloud 
the syllables himself, the kinsesthetic processes involved in 
pronouncing them will, of course, be present in full strength; 
yet apparently even here the absence of attention is a disad- 
vantage. The reason for this would seem to be that when we 
attend to the impressions we are committing to memory, not 
only are new associative dispositions formed, but the various 
tentative movements which occur set old movement systems 
into activity and enter into auxiliary new ones. Thus the 
greater the variety of tentative movements which a series of stimuli 
sets up, the better that series will be recalled, because, on the one 
hand, a number of new systems will be formed, and, on the other 
hand, advantage will be taken of all possible old ones. A series 
of syllables inattentively read aloud will be connected solely by 
the associative dispositions set up between the movements in- 
volved in pronouncing them, while a series attentively read 
aloud will be connected by the movements involved in pro- 
nouncing them, the movements involved in listening to them, 
the movements involved in looking at them, the movements 
involved in noting their place in the series, and the move- 
ments involved in noting their associations with words, the 
words being already united in old movement systems. 

That the first presentation of the objects between which an 
associative disposition is to be formed does far more than the 
rest in establishing the disposition is a fact ascertained by many 



106 MOVEMENT AND MENTAL IMAGERY 

experimenters. G. W. Smith (130), working at Harvard in 
1896, experimented with ten-syllable series, read through a slit 
in a screen, and tested by attempts to reproduce the series after 
one, three, six, nine, and twelve repetitions. The results showed 
that the first repetition did more for the learning of the series 
than all the others put together. Ephrussi (32), in 1904, had 
his observers read nonsense syllables or words a certain num- 
ber of times, and then tested the learning by the Method of 
Helps; that is, by counting the number of promptings the ob- 
server needed in reciting the series. The tests were made either 
at once, or after twenty-four hours; and the first presentation 
was shown to have more value than any of the others. Witasek 
(153) got the same result in comparing the value of reading 
and recitation. Pohlmann (111) reached a similar conclusion 
in 1906, counting the number of figures learned in three series, 
one presented once, the second twice, and the third three times. 
Knors (62) in 1910 used a similar method with syllables and 
words as well as figures, and confirmed the superiority of the 
first presentation; but he noted that it was not so marked when 
the testing was done by the Scoring Method; that is, by giving 
the odd-numbered syllables out of the series and requiring the 
observer to give all the even-numbered syllables that followed. 

The first presentation has also more effect than any of the 
others in bringing about recognition. Reuther's Method of 
Identical Series, where the observer is tested by noting the num- 
ber of elements in the series that he can recognize, confirms the 
superiority of the first impression, and Gamble, using smells as 
material and working with the Reconstruction Method, where 
the observer is given the members of the original series with 
their order destroyed and is required to rearrange them in the 
original order, tells us that in the first presentation the observer 
learned sixty per cent, of the series. Fischer (37) also noted the 
superior influence of the early repetitions in producing recog- 
nition. 

The first repetition is evidently the one that is made with 
fullest attention, so that a part at least of its superiority may 



LINKS IN MOVEMENT SYSTEMS 107 

be due to this fact. If it should turn out to be true that a repeti- 
tion reduces the resistance at synapses more, the greater that 
resistance is when the repetition occurs, this factor also would 
contribute to the effectiveness of the first repetition. We may- 
next ask whether all the repetitions after the first have equal 
value, or whether there are any other preferred positions for a 
repetition besides the first position. 

Hawkins (48), in 1897, testing the ability of sixth and seventh 
grade school children to recall groups of ten numbers immedi- 
ately after hearing them, noted the curious fact that the recall 
was poorer after two repetitions than after one. This was evi- 
dently an experiment on the memory after-image rather than 
on associative dispositions; and it is conceivable that a second 
reading of the numbers might have been made with certain 
differences of tone and accent that would tend to blur the 
memory after-image. Reuther (115) also found the second 
repetition rather a disadvantage than otherwise: his work, it 
will be remembered, was on recognition. No one, so far as I 
know, has observed that the second repetition is a disadvantage 
where recall after an interval — that is, recall based on supra- 
liminal associative dispositions — is concerned. But it does 
seem to be evident from the work of many experimenters that 
the repetitions which come immediately after the first one not 
only accomplish less than the first, but less than the repetitions 
which follow them.^ Ebbinghaus (29) declared that the next 
few repetitions after the first caused little increase in the saving 
effected on relearning; and that afterwards increase in the num- 
ber of repetitions caused increased saving, with certain fluc- 
tuations, until a limit was reached. The Saving Method, it will 
be remembered, measures the increase in both supraliminal and 
subliminal dispositions. Reuther, working on recognition rather 

^ Nagel (97) finds that the superiority of the first repetition is confined 
to its effect on the first and last syllables of the series, and that these owe 
their advantage to place associations, to the greater influence of immediate 
recall in the effect of the first repetition, and to their comparative immunity 
to the bad effects of perseveration. While he makes some valuable sugges- 
tions, his discussion on this point is far from clear to my mind. 



108 MOVEMENT AND MENTAL EMAGERY 

than recall, — that is, on subliminal rather than supraliminal 
dispositions, — finds that the amount correctly recognized 
increases with the number of repetitions at first more slowly 
than later; the repetitions immediately following the first one 
are less effective than those that follow them. Fischer (37) got 
evidence that the earlier repetitions in a series had more effect 
on recognition — that is, on subliminal dispositions — than 
on recall, — that is, on supraliminal dispositions. In Fischer's 
method, the observer was allowed to recall the syllables of the 
series if he could : if he could not recall a particular syllable he 
was asked to decide whether one supplied by the experimenter 
was right or wrong. The errors in recognition decreased much 
more rapidly after the earlier repetitions than later; the errors 
in reproduction decreased steadily as the number of recogni- 
tions increased. There would seem to be a perfectly conceivable 
reason for the fact that the repetitions just after the first one 
contribute relatively little to the strengthening of the associa- 
tive dispositions in the series as a whole. The syllables that are 
learned in the first repetition get for the next few repetitions 
more attention than the ones that have not been learned: the 
result is that these next few repetitions are more concerned 
with strengthening the dispositions of syllables already learned 
than in learning new ones. (A suggestion similar to this is 
made by Nagel (97) .) The same thing may happen later on in 
the learning process, so that after a few repetitions have gone 
to the acquiring of new syllables, the next few may be devoted 
to the further establishment of those already learned. Thus, 
Ephrussi found that the rate at which the amount learned in- 
creases with the number of repetitions undergoes marked 
fluctuations. 

Attention is the prime factor in still another aspect of the 
influence of repetition on the strength of associative disposi- 
tions; namely, the relation of the number of repetitions re- 
quired to the amount that has to be learned. When a long suc- 
cessive movement system must be formed, as, for instance, when 
a long series of nonsense syllables is to be learned, of course a 



LINKS IN MOVEMENT SYSTEMS 109 

greater number of associative dispositions must be established 
than when the movement system is short. Now, if it takes, 
say, twelve repetitions to enable one to recite a series of ten 
syllables correctly after a given interval of time, it will need 
more than twelve repetitions to enable one to recite a series 
of sixteen syllables correctly after the same interval. This is a 
fact with which we have everyday acquaintance in our at- 
tempts to memorize, and it seems self-evident that more time 
and labor should be needed to establish fifteen associative dis- 
positions than to establish nine. But is this, after all, seK-evi- 
dent.f^ The case is not like that of a hungry family each of whose 
members gets less food the larger the family. The nine associa- 
tive dispositions in the ten-syllable series each got twelve repeti- 
tions, and this was enough to bring them above the limen of 
recall: the fifteen associative dispositions in the sixteen-syl- 
lable series each got twelve repetitions, but for some reason 
they were not able to profit by their advantages as did the nine 
dispositions of the shorter series. Now, it will, of course, be true 
that only certain of the dispositions in the long series are left 
subliminal by the twelve repetitions. Others will be firmly es- 
tablished. The observer will be able to repeat a part of the six- 
teen-syllable series quite well, but not the whole. This fact, 
that the associative dispositions share unequally in the ad- 
vantage of the repetitions they have received, points clearly to 
differences in attention. While, if the observer has to read the 
syllables aloud, the kinaesthetic excitations which form the 
main links of the movement system are all present, yet, if some 
of the syllables are read with less and some with greater atten- 
tion, there will be differences in the tentative movements which 
may establish auxiliary associative dispositions and make use 
of dispositions established at some earlier time. For a fuller 
discussion of this subject the reader is referred to the treatment 
of "aids," in Chapter VII. Now, in a long series there is obvi- 
ously more chance for variation in the degree of attention than 
in a short one; hence the number of repetitions which will suf- 
fice to make all the dispositions of a short series suprahminal, 



110 MOVEMENT AND MENTAL IMAGERY 

because they are uniformly attended to, will not suffice for a 
longer series because some of its dispositions must be estab- 
lished under imfavorable conditions of attention. Does the 
number of repetitions required increase proportionately to the 
length of the series? If you double the length of the series, must 
you double the number of repetitions in order to learn it? 
There is a curious contradiction in the results of different in- 
vestigators here, but it is one that is not hard to explain. 
Ebbinghaus (29) declared that the number of repetitions in- 
creases much more rapidly than the length of the series. He 
found that while it took an average of thirty repetitions to 
recite a sixteen-syllable series correctly, it required fifty-five 
repetitions to recite a twenty-six syllable series correctly. But 
he was testing the learning by immediate recall of the series, 
which, of course, involves the memory after-image to a large 
degree, and this would naturally give a high advantage to the 
shorter series. Practically all later investigators, working with 
delayed recall, which involves only associative dispositions, 
find not only that the number of repetitions does not increase 
more rapidly than the series length, but that it increases less 
rapidly. Within limits, the more you have to learn, the more 
you can learn: if you are set to learn a series of twenty syl- 
lables, while you need more repetitions than are required to 
learn a ten-syllable series, you will not need twice as many. 
(Meumann (81), Weber (149), Radossawljewitsch (113), Knors 
(62) .) This is especially true of practiced observers : they learn, 
as Meumann says, to adapt attention to the task. It holds 
also for the subliminal dispositions involved in recognition: 
Reuther found that the absolute quantity recognized by the 
Method of Identical Series increased with the series length, and 
Gamble reports that with the Reconstruction Method, prac- 
tice actually tends to make the number of repetitions required 
for long and short series equal. This operation of "adapting 
attention" to the task is really an effect of what is called the 
* problem idea.' The nature of the influence of problem ideas 
will be discussed in a later chapter. Probably the adaptation of 



LINKS IN MOVEMENT SYSTEMS 111 

attention involves the use of different methods and helps for 
long and short series, and this is why practiced observers, who 
are expert in the use of helps, show especial ability in adapting 
themselves to long series. 

Another fact, connected with the influence of repetition on 
associative dispositions, which must be explained by referring 
to the effect of problem ideas, is the following. When suc- 
cessive movement systems are to be formed, as soon as a dis- 
position becomes supraliminal, it gains more in strength from 
being used for recall than from merely being reinforced through 
a new presentation of the material to be learned. Every one 
must have experienced the good eft'ect of an attempt to recite 
something that is partly learned. One may not get through 
without having to be prompted, but the associative dispositions 
that were strong enough to function seem even to introspection 
far more firmly established by having been depended on for 
recall. Witasek (153) in 1907 and Katzaroff (61) in the follow- 
ing year tested the beneficial effect of attempted recitations 
under laboratory conditions, and both found it to be far greater 
than that of a new reading of the material to be learned. Now, 
why should this be true? Suppose that a person is set to read 
through a series of words or syllables to be memorized. The 
sight of each syllable produces the movements of articulating 
it, and these movements produce kinsesthetic excitations. 
Gradually, the kinsesthetic excitations from one syllable make 
connections with the movements involved in pronouncing the 
next, so that the movement system is formed. Suppose that a 
sujBScient number of readings has occurred so that weak but 
supraliminal associative dispositions have been founded; that 
is, the observer is able, with hesitation and uncertainty, to 
recite the series "without book." In the course of the recita- 
tion, the nervous process has to travel the paths of the associa- 
tive dispositions that have been founded, and of course, as it 
travels them, it lowers their resistances. But why should it 
lower them more than they would be lowered by an additional 
reading? For in a fresh reading, too, the nervous process must 



112 MOVEMENT AND MENTAL IMAGERY 

travel along the paths where associative dispositions are being 
founded; otherwise a fresh reading would do nothing at all to 
strengthen the associative dispositions; whereas, of course, it 
does a great deal. The value of a recitation from memory as 
compared with that of a new reading seems to be a matter of 
the attitude of the learner; of the problem which he sets him- 
self. As such, we shall discuss it in Chapter VIII. 

The important question as to the most favorable interval 
between repetitions, since it involves the effect of time on 
associative dispositions, will be considered in the next section. 

The effect of repetitions changes its character somewhat as 
all the dispositions of the movement system that is being es- 
tablished become supraliminal. In the earlier stages of learn- 
ing attention is of the greatest value to a repetition; that is, 
each syllable, for instance, of a series to be learned must be 
attended to. In this process of attention a variety of tentative 
movements associated with tlie syllable are excited, and if any 
of these movements fit into old, already established movement 
systems, such systems act as aids to the establishment of the 
new one. When we begin to learn the names of the cranial 
nerves, attention to each name helps us to link their initials with 
the rhyme " On old Manasseh's peaked tops " : the rhyme makes 
sense of a kind; that is, its words involve movement systems 
already formed. The first few times the list of nerves is recited 
from memory this auxiliary system comes much into play. But 
if the list is often repeated after it has reached the point of cor- 
rect recitation, if it is *overlearned,* then gradually the need 
for the auxiliary systems falls away. The new system becomes 
thoroughly established in its own right: the pronunciation of 
one name will be a sufficient stimulus to the pronunciation of 
the next. The process becomes * automatic,* which expression 
means in this connection simply * independent of aids from 
other movement systems.' At this stage it does not matter 
whether the repetitions are made with attention or not. 

The effect of repetitions is different also when the movement 
system to be formed is very complex. Bryan and Harter (17) 



LINKS IN MOVEMENT SYSTEMS 113 

studied the effects of practice on learning to telegraph, and 
Book (13) made a similar study of the effect of practice or 
repetition on typewriting. Both these activities involve, first, 
the formation of a number of simple movement systems, and 
second, the formation of a number of complexer systems. In 
learning to typewrite, for instance, one begins by forming an 
associative disposition between a letter and a particular finger 
and arm movement, required to strike a particular key on the 
board. Writing a sentence means at this stage that each letter 
is attended to and sets off the proper movement. Later, words 
often recurring, like *the,' *that,' *and,' have links set up be- 
tween the various hand movements involved, so that the move- 
ments for each word become independent systems. The same 
process may later make independent systems out of the move- 
ments involved in writing familiar phrases. Now, at the point 
where the change, say, from the single letter or spelling-out 
type of association to the word-unit type occurs, an in- 
crease of attention and of effort is needed. It will not do to 
leave the repetitions to bring about improvement of their own 
accord. If left to themselves, they follow the older type, and 
the new systems will not be formed. The fact seems to be that 
repetition strengthens a single associative disposition first with 
the aid of older, already formed dispositions, aids, memory 
devices: this requires attention. Later it strengthens the dis- 
position without such aids. The strengthening shows itself by 
increased speed in the functioning of the associative disposi- 
tions : thus, in a process like that of typewriting a sentence, the 
time required will diminish. After a certain number of repeti- 
tions the time will be reduced to a minimum: it will be impos- 
sible to perform the function any faster. Further repetitions 
beyond this point will doubtless have an effect on the per- 
manence of the learning, but they cannot affect the speed of the 
performance. Now is the time for the formation of connections 
between the dispositions, for grouping them into systems of 
higher order, for typewriting, for instance, bywords and phrases 
instead of letters. But the formation of these new systems 



114 MOVEMENT AND MENTAL XMAGERY 

requires attention, and so the process of having recourse to aids 
begins all over again; resulting often in a new access of speed 
as the new systems in turn become automatic. 

The influence of fatigue is, of course, an important factor in 
the effect of repetitions. If the learning process is in a stage 
which requires attention, it is evident that the fatigue which 
attends it may be either fatigue connected with the attitude of 
activity involved in learning, or fatigue connected with the 
process itself that is being learned. Take for example the task 
of learning a series of nonsense syllables. To learn them quickly 
involves keeping steadily in action the problem idea of learn- 
ing, the effort or will to learn. The fatigue connected with the 
maintenance of the attitude of activity which always functions 
whenever there is intellectual effort is discussed in the chapter 
on the problem idea. Its occurrence is probably responsible for 
those fatigue sensations which we call sensations of boredom 
or ennui: we are not really fatigued with repeating the syl- 
lables, but we are fatigued with attending to them: we should 
like to relax the activity attitude for a time. Later on in the 
learning process there may be set up actual fatigue of the proc- 
esses of articulation involved in learning the syllables. 

///. The Effect of Time 

No feature of our experience is more familiar than the fact 
that time effaces the past from our minds; that the movement 
systems formed in the course of our experience gradually weaken 
in their connections; that associative dispositions sink by the 
mere lapse of time to that subliminal state where they can no 
longer function to bring about recall. As dispositions grow 
weaker they act more slowly: Muller and Pilzecker (90), in the 
research which introduced the Scoring Method to psychologists, 
found that the longer the interval which has elapsed since an 
associative disposition was founded, the more slowly it acts in 
recall. If nonsense syllables are learned in groups of two, and 
if later the first syllables of the various groups are given in 
altered order, the observer being asked to supply the correct 



LINKS IN MOVEMENT SYSTEMS 115 

second syllable in each case, it will take him longer to do so, 
when an interval of six minutes has elapsed since the learning 
than if the interval has been only one minute. And when the 
strength of dispositions is measured by the Saving Method 
— that is, by the amount of time and labor their existence 
saves in reiearning — the decrease of their strength with the 
lapse of time is apparent. 

But the falling off in association strength with time does not 
occur at a uniform rate. This fact is well known to all students 
of psychology. One of the first results of the modern experi- 
mental investigations of memory to find its way into the 
textbooks was Ebbinghaus's (29) alleged law with regard to 
the rate of forgetting, that the ratio of the amount retained to 
the amount forgotten varies inversely as the logarithm of the 
time that has elapsed since the learning. This means, of course, 
that one forgets very rapidly at first and much more slowly 
later. The truth of this latter statement has been confirmed 
by subsequent investigators using other methods, although 
the rate of decrease is probably not so fast as Ebbinghaus's 
law requires. Ebbinghaus's experiments consisted in learning 
eight thirteen-syllable series and reiearning them after intervals 
of twenty minutes, one hour, nine hours, one day, two days, 
six days, and thirty-one days. The results were stated in terms 
of the ratio of the time saved in the reiearning to the original 
learning time: thus it might take, say, twenty minutes to learn 
the series the first time, and sixteen minutes to relearn it after 
an interval of two days: then the strength of the associative 
dispositions after a lapse of two days would be represented by 
the fraction 4^o. Radossawljewitsch (113) also used the Saving 
Method, with intervals of five, twenty, sixty, and four hundred 
and eighty minutes, and of one, two, six, fourteen, twenty-one, 
thirty, and one hundred and twenty days. But while Ebbing- 
haus, who was his own observer, counted a series learned, or 
relearned, if he could once recite it correctly, Radossawljewitsch 
counted it learned or relearned only if two correct recitations 
could be made. His results showed a much less rapid initial 



116 MOVEMENT AND MENTAL IMAGERY 

falling off with time than did those of Ebbinghaus. Finken- 
binder (36) employed a somewhat different method: the syl- 
lables were presented slowly. One every two seconds, and the 
learning or releaming was considered complete if the observer 
on seeing one syllable could just recall the next one. Practice 
and fatigue conditions were carefully controlled. The intervals 
used were half an hour, one, two, four, eight, twelve, sixteen, 
twenty-four, thirty-six, forty-eight, and seventy-two hours. 
The results lay between those of Ebbinghaus and Radossawl- 
jewitsch as regards the rate of forgetting. The comparatively 
slow rate at which the dispositions in the latter's experiments 
fell away with time thus seems to have been due to the fact 
that they were especially strong, since the test was two correct 
successive recitations. 

In Miiller and Pilzecker's (90) study with the Scoring Method 
it appeared that when the association times for syllables 
learned eleven minutes before were compared with those for 
series learned twenty-four hours before, the difference was 
slight. Apparently if an associative disposition maintains after 
the first ten minutes enough strength actually to reproduce the 
second term of the association, it will continue to perform its 
function with about the same readiness for at least twenty- 
four hours. 

But before asserting on the basis of these experiments that 
weak associative dispositions fall off very rapidly just after 
they are established and more slowly later, while stronger ones 
fall off less rapidly at first ("When the over-learning has been 
carried to a very high pitch — to so high a pitch that a very 
large share of the associations involved have been reduced to a 
condition of automatic efficiency, then the onset of forgetting is 
extremely slow,'* say Ladd and Woodworth in their "Physio- 
logical Psychology," pages 576-77), we must consider the 
inferences to be drawn from experiments on another problem. 
This is the problem of the best distribution of repetitions. When 
Lottie Steffens (132) was engaged in finding whether the most 
economical method of learning is to read the material straight 



LINKS IN MOVEMENT SYSTEMS 117 

through from beginning to end a number of times (Whole 
Method) or to break it up into sections and learn each part 
separately (Part Method), it occurred to her that one among 
other reasons for the superiority she found in the Whole Method 
might be the fact that this way of learning made a longer time 
elapse between two repetitions of the same syllable. Is it per- 
haps true that if a given time be allowed for learning, the best 
results will be obtained when the repetitions of the material to 
be learned are most widely distributed through the interval? 
Ebbinghaus had found indications that such was the case. To 
test the supposition further, Steffens made her observers learn 
series of eight nonsense syllables according to three different 
plans, A, B, and C. By plan A, a series was read once: then 
there was a pause equal to the time of one rotation of the 
kymograph drum on which the syllables were being shown, 
then another reading, then another pause, and so on until there 
had been six readings and six pauses. Then the series was re- 
peated without intermission until it could be recited without 
error. Plan B was to give three readings in immediate suc- 
cession, then a pause equal to the time of three rotations, then 
three more readings, followed by a second pause equal in 
length to the first: there ensued as before repetitions in direct 
succession until the series was learned. In plan C, the series was 
given six readings in direct succession: then came a pause equal 
to six rotations of the kymograph, and then the learning pro- 
ceeded as in the other cases. It was found that the number of 
repetitions needed at the end to produce perfect learning was 
least when plan A was used. Other experiments with longer 
pauses confirmed the superiority of distributed repetitions. 

Jost (59) undertook to give the law of the superiority of dis- 
tributed repetitions a more thorough investigation than it had 
had from either Ebbinghaus or Steffens. He compared the 
learning of twelve-syllable series by thirty repetitions on a 
single day with the learning of similar series by ten repetitions 
on each of three days, testing the learning each time by the 
number of repetitions required to relearn after twenty-four 



118 MOVEMENT AND MENTAL IMAGERY 

hours. The distributed series showed greater saving. The most 
obvious explanation for this result would be that thirty or more 
repetitions in immediate succession are so fatiguing that the 
last ones have little value. Jost in the following way excluded 
fatigue as an explanation. The thirty repetitions on a single 
day were divided into six groups of five repetitions each, and 
between each group and the next, ten repetitions were made of 
one of the series which were being learned at the rate of ten 
repetitions a day. Thus, the ten-a-day series should have been 
more fatiguing to learn than the thirty-a-day. But the former 
still gave a higher saving in the relearning. 

Now, we have seen that the first repetition of a series has 
greater value than any of the repetitions which follow, be- 
cause it gets most attention. If this is true not only of the very 
first repetition of all, when the series is first presented to the 
observer, but of the first repetition of any group of repetitions 
even when the series has been shown in earlier groups, then an 
explanation of the superiority of distributed repetitions would 
lie in the fact that they furnish a greater proportion of first 
repetitions. Jost rejects this explanation on grounds which do 
not seem satisfactory. He holds that the very first repetitions 
have not so much attention value as those coming a little later, 
because attention takes time to adapt itself. Hence he thinks 
if attention were the chief factor, a division into groups of four 
ought not to be so advantageous as a division into groups of, 
say, eight: but the results show that the smaller groups are 
most effective. There is however plenty of evidence that the 
very first repetition of all has superior attention value, and one 
cause of the advantage of distributed repetitions, it is natural to 
suppose, must lie in their greater proportion of first repetitions. 

Jost himself finds the chief reason for the superiority of dis- 
tributed repetitions in the influence of the age of associative 
dispositions on the rate at which they fall off with time. The 
relearning of the series learned by thirty repetitions in im- 
mediate succession was done twenty-four hours later. The 
relearning of the series learned by ten repetitions on each of 



LINKS IN MOVEMENT SYSTEMS 119 

three days was done on the fourth day: two-thirds of its previ- 
ous repetitions had thus occurred at a longer interval before the 
relearning than was the case with the thirty-a-day series. *'If 
two associations," says Jost, "are of equal strength but dif- 
ferent age, a new repetition is more valuable for the older one." 
The truth of this statement he proved in the following way. 
The method of testing the strength of an associative disposi- 
tion by relearning gives the material new repetitions: the 
method of testing by association time, the Scoring Method, 
does not. Now, suppose that two series of syllables be read n 
times, and tested after an interval U one of them by the relearn- 
ing or Saving Method, the other by the Scoring Method. Sup- 
pose, further, that two other series are read n — x times, — that 
is, a smaller number than the first two series, — and are tested, 
one by the Saving, the other by the Scoring Method, after an 
interval t—x, less than the first interval. The associative dis- 
positions of these last two ought to be of nearly equal strength 
with those of the first two, Jost argued, since, although they 
have had less time in which to decay, they were not so strong at 
the outset, having been formed with fewer repetitions. The 
two pairs of series therefore fulfil the condition of being equal 
in strength but unequal in age. If Jost's hypothesis is correct, 
the Saving Method of testing, which involves giving new repeti- 
tions, should give better results with the older series, while this 
result should not appear in the tests by the Scoring Method. 
Jost reports that the results of the experiment fall out in ac- 
cordance with this expectation. And he explains his first hypoth- 
esis of the greater value of a new repetition for an older asso- 
ciation, by a second one: "If two associations are of equal 
strength but different age, the older diminishes less with time." 
Lipmann (72), working by the Scoring Method, finds that if a 
young and an old series of associative dispositions give an equal 
number of right associates, the number of scores is increased 
by new repetitions more rapidly in the case of the latter; which 
confirms Jost's statement that a new repetition is more valu- 
able for an older disposition. 



120 MOVEMENT AND MENTAL IMAGERY 

The superiority of distributed repetitions has been found 
to exist in the case of movement systems which involve other 
muscles than those of articulation. In some instances, as in 
Book's (13) study of learning to typewrite, the factor of fatigue 
is obviously the dominant one, and the distribution of repeti- 
tions resolves itself into a matter of the distribution of periods 
of rest. In the Vassar laboratory, intervals of one minute were 
found to be more favorable than no intervals between repeti- 
tions in learning a series of hand and arm movements in shuf- 
fling cards (15). 

Now it is evident that two distinct factors enter into all the 
manifestations of the * strength' of an associative disposition. 
The functioning of such a disposition involves the excitation 
of a motor pathway by a nervous current which passes over 
certain synapses from a kinsesthetic sensory pathway. The 
degree of excitation thus produced will depend, first, on the 
lowered resistances at the synapses in question. This resistance 
is lowered each time the nervous ciu'rent crosses the synapses : 
it is therefore a function of the number of repetitions of the 
series of movements. We may call this the frequency factor. 
But, secondly, the degree to which the motor pathway is 
excited will depend on its readiness to respond. We have seen 
that the memory after-image is caused, probably, by the fact 
that immediately after a motor pathway has discharged, it is 
in a state of readiness to discharge again on the slightest prov- 
ocation. This readiness may indeed depend also on lowered 
synaptic resistances, but the synapses involved would seem to 
be not particularly those from the kinsesthetic pathway which 
has just discharged it, but any or all the synapses which lead 
into it. This factor of readiness to renew discharge, while it 
is strong enough to produce apparently spontaneous recall of 
imagery only for a short time after the original excitation, 
except in the cases of perseveration, probably continues with 
diminishing intensity for some time. It is clearly a function of 
the recency of the excitation of the motor pathway, and we may 
call it the recency factor. 



LINKS IN MOVEMENT SYSTEMS 121 

When a series of movements has been repeated a number of 
times, the ease with which it can be immediately reproduced 
depends then on a combination of the frequency and recency 
factors. Now the recency factor falls oiff quite rapidly with 
time. We may suppose that the frequency factor falls off much 
less rapidly. Immediately after the learning, the rate of forget- 
ting is rapid, because the recency factor is dropping out. The 
rate at which it will drop out depends on the various causes 
which strengthen the memory after-image; a set of conditions 
which has been quite inadequately investigated. Ji the number 
of repetitions has been just enough to produce one correct 
recitation, it is probable that the correctness of the recitation 
depends largely upon the memory after-image or recency 
factor, and we may expect a very rapid falling off with time. 
If two correct recitations are made the test of learning, the fre- 
quency factor will come more into play, and the falling off with 
time will be less steep. Where the number of repetitions is very 
great, much beyond that needed for even two correct recita- 
tions, the recency factor sinks to comparative insignificance, 
and the learning lasts indefinitely. In fact, the question may be 
raised as to whether time has any effect at all on the frequency 
factor, the lowered resistances at the synapses between the 
kinsesthetic pathway and the motor pathway: whether the 
process of forgetting is not wholly due to the decay of readiness 
on the part of a motor pathway to be excited. The fact is that 
we do not very often bring the frequency factor to a point 
where it overpowers the recency factor. Most of our learning is 
done more or less with a view to quick forgetting. We are 
satisfied if we can recall after a brief interval. It is mostly the 
movement systems connected with the larger bodily activities 
that get really enough practice to make frequency independent 
of recency. We never forget how to skate, how to swim, how 
to use the typewriter. Most of our verbal movement systems 
are formed with very few repetitions, indeed, compared with 
the amount of repetition given to such movement systems as 
these. 



122 MOVEMENT AND MENTAL IMAGERY 

The rapid initial forgetting would then be due to the falling 
off in the recency factor, the perse verative tendency. This 
would be more marked, the less the frequency factor was in- 
volved; hence Radossawljewitsch, who required enough repeti- 
tions of his material to produce two perfect recitations, found 
a less rapid rate of forgetting at first than did either Ebbing- 
haus or Finkenbinder, who required only one perfect recita- 
tion. 

Now what about the superiority of distributed repetitions.'^ 
WTien a motor pathway has just been excited, it is in a state of 
readiness to discharge again. This must mean that all its 
synaptic resistances are low. The next repetition following im- 
mediately upon the first, and finding low resistances, obviously 
cannot lower them much more. Its effect on them, we may sup- 
pose, is therefore slight. Since the * readiness,' the recency 
factor or perseverative tendency, diminishes with time, the 
learning that is done with no interval will naturally be short- 
lived in its effects: it will depend much on the recency factor 
and little on the frequency factor. The superiority of distri- 
buted repetitions may then be due, not only to the absence of 
fatigue and the large proportion of first repetitions with their 
high attention value, but to a law which seems inherently 
probable: namely, that a nervous process, in traversing a 
synapse, cannot produce any permanent effect on that synapse 
if little or no resistance is offered to it. 

IV. The Interference of Associative Dispositions in 
Successive Systems 

Associative dispositions which are called into action suc- 
cessively may interfere with each other, instead of readily 
forming themselves into a successive movement system. 
There is an especial difficulty of this sort about the case where 
the movement system to be formed involves the same move- 
ment repeated a number of times in different contexts. We all 
know that a passage of prose or verse is particularly hard to 
learn if the same phrase occurs in it repeatedly, set each time 



LINKS IN MOVEMENT SYSTEMS 123 

in different surroundings: in learning a part in a play one is 
especially likely to trip over speeches that begin with the same 
words but end differently, or that involve the same thought 
put in slightly different words. Bourdon (14) and Ransch- 
burg (114), using numbers as the material to be learned in their 
experiments on memory, both found that numbers are more 
readily learned, the fewer like figures they contain. The effect 
of the repetition of like elements in different settings may be 
formulated by saying that immediately after the movement 
sequence A-B is presented, tending to establish the associative 
disposition A-B, another movement sequence A-C occurs, tend- 
ing to establish the associative disposition A-C. Mtiller and 
Pilzecker (90) said that if A has just been associated with B, 
this fact exerts a generative inhibition on the formation of the 
association A-C. Physiologically, one may conceive that since 
the pathway for B is still in readiness, having been so recently 
excited, when A is given the second time its kinsesthetic energy 
is divided between the old path A-B and the new path A-C. 
\Mien the time for recall comes, when we try to repeat from 
memory the material we have learned, then the two dispositions 
are simultaneously set into action by A. Now, it may happen 
that they lead to perfectly compatible movements, such, for 
instance, as those involved in seeing a word and hearing it pro- 
nounced: under such conditions we have the formation of a 
simultaneous movement system, a process which will be con- 
sidered in the next chapter. But if they are not compatible 
movements, and cannot both be carried out at the same time, 
there occurs in recall the process of interference which Miiller 
and Pilzecker called effectual inhibition. If A tends to set into 
activity the incompatible motor processes B and C, then there 
may be for a few seconds a deadlock, both responses being in- 
hibited. This regularly shows itseff, of course, in experiments 
where the time of recall is being measured, as a lengthening of 
the time. Hence many experimenters (for instance, Cattell 
(21), Munsterberg (93), Wells (150)) find that *free' associa- 
tions, where the observer is at liberty to think of any word he 



124 MOVEMENT AND MENTAL IMAGERY 

likes in connection with a given stimulus word, take longer than 
* forced' associations, where the observer is directed before- 
hand to think of, say, a rhyming word or a word with opposite 
meaning to that of the stimulus word. Again, stimulus words 
that refer to recent experience are reacted to slowly because 
they set into action so many dispositions. Hirszowicz (51) re- 
ports that abstract words, also, which have fewer associative 
dispositions connected with them, are responded to more 
promptly in such association time experiments than concrete 
words. 

A period of mutual inhibition of this kind may be terminated 
by the victory of the stronger associative disposition. Calkins 
(19) undertook in 1895 to study the relative strength, in such a 
contest, of dispositions which had the advantage of recency, 
those which had the advantage of frequency, and those which 
had the advantage of greater attention at the time of their 
formation. She presented to her observers colors followed or 
accompanied by numbers. One of the colors occurred several 
times in the series, once in an unimportant position, and once in 
some emphasized situation, either again with the same nu- 
meral, or at the beginning or end of the series (with another 
numeral), or with a numeral of unusual size or color. Other 
experiments were made where a given color appeared, in a long 
color-number series, three times followed by the same two- 
digit numeral and once followed by a three-digit numeral, 
which as the only one of its kind would naturally attract especial 
attention; or three times with the same numeral and once at 
the beginning of the series with a different number, which as 
the first number of the series would get more attention. Also 
there were short series where the color shown last had ap- 
peared once before with a three-digit number, or at the begin- 
ning with another number, or twice before with the same num- 
ber, which was different from the one associated with it when 
it was shown last. After each series the colors were presented 
without their numbers, one at a time, in altered order, and the 
observer was asked what number the color recalled. Thus a 



LINKS IN MOVEMENT SYSTEMS 125 

color A had formed associative dispositions with two different 
numbers, B and C; in some cases the disposition A-B had the 
advantage of recency, when the color A and number B were 
the last ones shown; sometimes A-B had the advantage of fre- 
quency, and sometimes B had been presented in such a way as 
to attract especial attention. Under these conditions, the re- 
sults showed that frequency gave the greatest advantage; the 
degree of attention came next, and recency had third place 
only. It is not surprising that the recency factor was of com- 
paratively little importance here, for all the numbers really had 
the advantage of recency. The series were not long enough to 
permit the recency or perseverative tendency to die out in any 
of the motor pathways involved. 

Miiller and Pilzecker called attention to the fact that when, 
after the associative disposition A-B has been formed, A is 
presented with C, even such a presentation with a new associate 
may strengthen the old disposition A-B. For the instant after 
one reads the new syllable C, one may recall ^'s old associate 
B, and since it seems to be a law that the functioning of an 
associative disposition in actual recall does more to strengthen 
it than the renewed impression of its terms through the sense- 
organs, A-B is more helped than it would be if B were actually 
presented. Closely connected with this fact, which Mtiller and 
Pilzecker called * associative co-excitation,' is a curious result 
obtained by Mtiller and Schumann (91). Although, as we have 
seen, the disposition A-C will not be so readily established if the 
disposition A-B already exists, the establishment of the new 
disposition A-C seems to do no harm to the one already on the 
scene. Mtiller and Schumann found that if the disposition 
A-B has so far weakened with age as to have become sub- 
liminal; if, that is, A will no longer recall By it can be rees- 
tablished by even fewer repetitions, when A has in the mean- 
time become associated with C, than when no new dispositions 
have been formed. For example, let us say that the syllable 
*con* has been learned in connection with the syllable *seb,* 
but that the learning occurred so long ago that *con' now fails 



126 MOVEMENT AND MENTAL IMAGERY 

to recall *seb.' In a new series, *con' is learned in conjunction 
with the new syllable * mup.' After this series has been learned, 
the old one, in which * con* is followed by *seb,' is relearned, and 
although in the first repetitions of this old series the new asso- 
ciation ' con-mup ' exerts some interference, the bringing of the 
old disposition * con-seb * above the limen of recall takes place 
with fewer repetitions than if the new disposition * con-mup' 
had not been established. It is hard to understand this except 
on the supposition that * associative co-excitation * occurs below 
the limen of actual recall, so that the old dispositions are sub- 
liminally practiced while the new ones are being founded. 

No such furthering effect occurs when, immediately after an 
associative disposition has been founded, other dispositions 
which do not involve either of the terms of the old one are 
established; if, that is, just after the disposition A-B has been 
formed, the dispositions C-D and E-F are founded. If one fills 
the pause between learning a series and testing its learning, for 
example, with the learning of other series, or with any kind of 
intellectual work, the results of the test are unfavorably af- 
fected. This is of coiu'se one of the factors which make a long 
series of syllables harder to learn than a short series. It is 
termed by Muller and Pilzecker retroactive inhibition. It helps 
to explain also why the middle of a series should be the part 
hardest to learn. For the middle syllables of a series suffer 
interference from the memory after-images of their predeces- 
sors and retroactive inhibition from their successors. (Poppel- 
reuter (112) uses the term * anterograde detraction* to desig- 
nate the interference exerted on associative dispositions by the 
memory after-image processes of preceding impressions, and 
'retrograde detraction* to designate retroactive inhibition). 
The physiological cause of retroactive inhibition can hardly be 
conceived otherwise than as an interference with processes of 
recall that would, without the distraction, take place in the in- 
terval between learning and testing. It may be supposed that 
if one were not given the new material to learn just after the 
learning that is to be tested, one would occupy at least a part 



LINKS IN MOVEMENT SYSTEMS 127 

of the interval in recalling the old. So far as I know, no experi- 
ments have been made to disprove such a supposition. The 
only way in which such recall can be prevented is by giving 
the observer something to do in the interval, which would of 
course produce the effect of retroactive inhibition. 



CHAPTER VII 

SIMULTANEOUS MOVEMENT SYSTEMS 

A SIMULTANEOUS movement system is one where the move- 
ments, instead of being dependent each on the one which pre- 
ceded it in time, are mutually interdependent and occur to- 
gether. The linking by associative dispositions takes place in 
both directions, or in all directions if the system is composed of 
more than two movements. Not only are the kinsesthetic 
excitations produced by the movement^ the necessary stimulus 
to movement J5, but the excitations resulting from B are the 
stimulus to movement A. It is evident that in such systems the 
component movements must be compatible. They must be of 
such a nature that they can be performed at the same time. 
Thus two articulatory movements could not enter into a simul- 
taneous movement system: you cannot pronounce t and b at the 
same moment. But the movements involved in pronouncing a 
word and those involved in looking at the word printed, or call- 
ing up a mental image of its appearance, are compatible, and 
could enter into a simultaneous system. In our perceptions of 
objects, some of the movements are compatible and enter into 
simultaneous systems, while others do not. 

An originally simultaneous system is formed by the actual 
occurrence of the movements together, and strengthened by 
each repetition of their synchronous occurrence. Meyer (83), 
in 1910, following a method suggested by Ach, tried to bring 
about the formation of simultaneous systems under experi- 
mental conditions. The observer was shown a series of cards, 
each card carrying two groups of simple figures, and each shown 
for the very short instant of 135 thousandths of a second: the 
interval between each card and the next was the same very 
brief time. In the test, the observer was shown one half of the 
card and required to draw from memory the figures that were 



SEVIULTANEOUS MOVEMENT SYSTEMS 129 

on the missing half. The brief exposure was intended to keep 
the observer from attending successively to the two halves of 
the card, and force him to attend to them simultaneously. 
The short interval between exposures would, it was thought, 
in a similar way keep him from attending successively to the 
two parts of the memory after-image of the card. Learning and 
correct recall proved to be possible by this method. It is evi- 
dent that only those parts of the card could really be simul- 
taneously attended to which did not involve incompatible 
movements. It is also evident that most of the learning which 
we do in ordinary life is performed under conditions very differ- 
ent from these. 

Where the movements which enter into the system are very 
simple, they may form themselves into simultaneous systems, 
probably, by actually occurring together. But in all the con- 
crete examples one can think of where simultaneous systems 
are formed, one comes to do the two things together, or attend 
to them together, through a preliminary process of attending 
to them alternately. The leg and arm movements of a prac- 
ticed swimmer form a simultaneous system, but in learning to 
swim they are performed alternately, and even after one really 
begins to swim one has difficulty in not attending to them 
alternately. The static movement system of holding the head 
perfectly still and the phasic system of the arm swing are formed 
into a simultaneous system when one learns to make a golf 
stroke, but their simultaneous performance is possible only by 
having attended to them alternately as a beginner. When one 
has perfectly learned a language, the sight of a word and its 
meaning are simultaneous; but in the beginning one attended 
alternately to the printed word and the idea of its meaning. 
When associative dispositions leading in both directions are 
formed between two movements, so that either one can excite 
the other successively, if they are compatible movements the 
tendency is apparently always for them to form simultaneous 
systems. The greatest aid to the formation of simultaneous 
systems is the association of each of the two movements with 



130 MOVEMENT AND MENTAL BIAGERY 

a common third. If C and B are compatible movements, and 
associative dispositions have been formed between A and C 
and between A and B, then when A occurs, there is a tendency 
for B and C to be simultaneously excited. Thus Miiller and 
Pilzecker (90) found that if a syllable such as *bez' were 
learned at one time in connection with the syllable *gaf,' and 
at another time with the syllable *iip,' when *bez' was later 
given the observer might respond with a kind of hybrid like 
'gap.' Both of the former associates of *bez' were reproduced, 
but the incompatible movements were forced out and a com- 
promise was reached in the combination of elements from both 
syllables. This method of forming simultaneous systems by 
linking each of several movements to a common motor response 
is of the utmost importance for our experience. It is precisely 
thus that those simultaneous movement systems are formed 
on which are based what we call perceptions of objects, as well 
as ideas of concrete objects and of abstractions. 

The perception of an object consists of a number of sensa- 
tions, some of which are peripherally excited, that is, caused by 
the activity of our sense organs at the moment, while others are 
centrally excited, that is, the revival of former sense experi- 
ences. A piece of ice looks smooth, white, hard, and cold: we 
realize that only the whiteness of it is the result of present sense 
stimulation, and that the hardness, smoothness, and coldness 
are the effects of former experiences with the senses of touch 
and temperature. Now the way in which we form such com- 
binations of sensations into perceptions is evidently not so 
much by adding bit to bit to form a mosaic, as by digging one 
bit after another out of an original whole. In first making ac- 
quaintance with an object we respond to it as an undiffer- 
entiated whole : later we come to make specialized responses to 
various parts and aspects of it; but it is the fact that it can be 
still responded to as a whole that keeps these specialized move- 
ments together in a single system, and thus gives the object its 
unity. An orange, or a chair, or a tree, is a single object, and 
not a mere aggregate of qualities and parts, because it can be 



SEVIULTANEOUS MOVEMENT SYSTEMS 131 

reacted to as a whole, and because every one of the movements 
involved in attending to its parts is associated with the move- 
ment of reacting to the whole object. Some of these movements 
which are associated with various parts or aspects of an object 
are compatible: the fact that they lead to the common outlet 
of a movement made to the whole object may thus transform 
them into simultaneous systems. Others are incompatible, and 
must be united in successive rather than simultaneous systems; 
thus, for instance, one cannot attend simultaneously to both 
ends of a pen, but the whole object is a unity because of the 
possibility of responding to the whole of it by a single movement 
or movement system. Of the motor responses thus linked to- 
gether by their common outlet, the compatible ones become 
simultaneous systems, relating to those parts of the object that 
can be attended to together; while the incompatible ones be- 
come successive systems, either reversible or irreversible, re- 
lating to those parts of the object which must be attended to in 
succession. 

On a non-motor theory of association, which would make 
the formation of an associative disposition result from a lower- 
ing of resistances at the synapses on a pathway directly con- 
necting two sensory centres, and resulting from their simul- 
taneous activity, it is commonly held that all associations are 
based on simultaneous rather than on successive experience. 
Thus Offner (98) says that when two successively occurring 
impressions are associated, it is because the second impression 
is simultaneous with the memory after-image or perseverative 
process of the first. Wohlgemuth (154) has recently maintained 
on the basis of experimental results that all association is be- 
tween simultaneously occurring experiences. He required his 
observers to form an association between a color and a form 
(a) when the form w^as colored; (6) when a black shape was 
shown on a colored ground; (c) when a colored field was shown 
alongside of a black shape on a white ground; (d) when a colored 
field was shown followed by a black shape on a white ground, or 
vice versa. It was found that " the more the members of a group 



132 MOVEMENT AND MENTAL BIAGERY 

are apperceived as a whole, the stronger their association with 
each other," and from this it is concluded that " all associa- 
tions are due to simultaneity." It is evident that the superi- 
ority of the associations in impressions that were apperceived 
as a whole, for instance, of the association between color and 
shape when the shape is itself colored, is due to the fact that 
besides the simultaneous responses made to the two factors of 
color and shape, there is a single response to the whole impres- 
sion; thus the simultaneous impression has the great aid of a 
single unifying motor reaction. 

Just as the unity of the perception of an object depends on 
the possibility of making a single movement or movement sys- 
tem in response to the object as a whole, so of course the pos- 
sibility of reviving a memory image of an object as a whole 
depends on such a single response. Upon the strength of the 
simultaneous and successive systems thus linked together by 
their common outlet will depend the completeness and ac- 
curacy with which a memory image can be analyzed into de- 
tails corresponding with the original. It is not necessary to 
emphasize the importance of a word or name as furnishing a 
convenient unifying response to the whole object. One cause 
of the low stage of intellectual development of animals is the 
very limited extent to which they can hold together the parts 
of their experience by making reactions to a whole group of 
such parts as a single group. Beasts that, like the monkey, the 
elephant, and the raccoon, have grasping organs with which to 
move things about have a great advantage so far as the forma- 
tion of perceptions of objects is concerned. But the unrivalled 
instrument of unifying motor responses is of course language. 
By its help we can not only hold together into a system our 
responses to the various aspects of a single concrete object, but 
we can in a similar way form systems out of the aspects or 
features which a number of objects have in common. We can 
form those systems which are the bases of general ideas or 
concepts, such as the concept dog or animal. There is almost 
no limit to the complexity of the system combinations which 



SIMULTANEOUS MOVEMENT SYSTEMS 133 

can be formed through having a single motor outlet for an en- 
tire combination. 

The process of learning practically always involves both 
simultaneous and successive movement systems. In trying to 
form a new successive system, such as a memorized series of 
nonsense syllables, one is of course really working not with 
single movements, but with systems of movements. Each syl- 
lable is not merely pronounced, which is a process involving 
comparatively simple simultaneous systems for each vowel and 
consonant, but there is very likely present a visual image of the 
syllable, betraying, if our theory is true, the presence of ten- 
tative eye movements; and there may be also other * aids' to 
the learning process, each one involving its own movement 
systems. 

When a number of stimuli, each calling for its own motor re- 
sponse, act together upon the organism, as of course they are 
constantly doing, one set of responses is prepotent, and other 
incompatible responses are completely inhibited. It goes with- 
out saying that the inhibited responses can form no associative 
connections. That which is wholly unattended to does not 
form associations. It is true that Scripture (123), working in 
the Leipzig laboratory more than twenty years ago, found that 
unattended-to parts of a picture, letters or small colored squares 
in the corner, for example, did when later shown alone recall 
the picture in a certain number of cases too large to be due to 
chance. But there is always a doubt as to whether, in these few 
cases, the elements which did the recalling were really unat- 
tended to, and Howe (53), repeating Scripture's experiments in 
the Cornell laboratory, failed to confirm his results. Ordahl 
(101) tested the question in 1911 by a better method: she had 
her observers learn the middle one of three ten-syllable series 
arranged in parallel vertical columns. After a short interval 
another set of three was presented whose middle series was one 
of the two side series in the preceding set. Would this middle 
series be better learned now because it was present, though 
unattended to, at the side of the series previously learned? The 



134 MOVEMENT AND MENTAL IMAGERY 

results showed that it was not any better learned; its presenta- 
tion without attention had formed no associative dispositions. 

A different problem, however, is furnished by the more ordi- 
nary cases of distraction. A thing to which we give no attention 
cannot be said to distract us at all: distraction occurs when our 
attention is forced to alternate between the movement system 
we are acquiring and another movement system quite uncon- 
nected with it. The effect of distraction seems to be greater, the 
more the two systems are, not merely disconnected with one 
another, but actually incompatible with one another. When 
they are really incompatible, if attention happens to be given 
to the distracting process the one to be learned is wholly shut 
out. Von Sybel (l36a) says that distraction diminishes visual 
learning in favor of auditory-motor learning. Thus its effect in 
general seems to be that of simplifying the movement system 
that is formed. It prevents the stirring up of the more complex 
systems involved in visual imagery and in meaning connec- 
tions. There are two ways in which one might conceivably ex- 
plain this effect. One would be by supposing that only a lim- 
ited amount of nervous energy is available in the cortex, and 
that if a part of it is occupied in the movements of the dis- 
tracting system, there will not be enough left for other com- 
plex movement systems. The other explanation would rest on 
the possibility that the distracting system might contain move- 
ments incompatible with those of the system to be learned; 
and of course the more complex the system to be learned, the 
greater the likelihood that some of its parts would be incompat- 
ible with those of the distracting system. Both of these sup- 
positions are very likely true. 

The most concrete problems connected with the mutual 
relations of movement systems concern the way in which large 
systems are secure from distraction. The ability of any process 
that is going on in the mind to keep itself from being disturbed 
by distractions depends mainly on two factors. The first is the 
amount of effort or resolution that is put forth to *keep one's 
mind on* the process to be attended to. This factor will be 



SIMULTANEOUS MOVEMENT SYSTEMS 135 

discussed in the chapter on "The Problem or Purpose." When 
the task is one of forming a new movement system, of learning, 
for instance, a series of nonsense syllables, nothing but effort 
will enable the material that is in process of being learned to 
hold attention against distraction. It will be suggested in the 
chapter just referred to that it is the naturally persistent char- 
acter of the attitude of activity or effort which enables the task 
associated with it to be held to, despite distracting influences. 
But often, of course, it is the interest of the material that holds 
distraction aloof. Now, interest always means that some large, 
already formed movement system is back of the material at- 
tended to, and that its momentum, so to speak, is such that the 
associative dispositions not involved in it will be inhibited. The 
advantage is always with the older and complexer systems. 
Thus Toll (139) had his observers learn lists of words in which 
names of mammals alternated with names of American cities. 
The results showed that the tendency of one word was almost 
never to recall the word that followed it in the series, but rather 
to recall, if it were an animal name, the name of another ani- 
mal; if it were a city name, the name of another city. The 
older and complexer systems had the right of way. 

Levy-Suhl (70) used the ability of a well-established system 
of associative dispositions to resist distraction as a test of the 
normality of the mind. Insane and normal persons were al- 
lowed to start a train of ideas suggested by themselves, and 
when it was well under way, they were interrupted by pro- 
nouncing to them an irrelevant word. Only a hopelessly ab- 
normal mind meekly accepted the distraction and followed the 
new line of thought without reference to the old. A curious 
instance of the effect of the problem or purpose involved in an 
experiment is shown by the fact that Baldwin (8), trying ex- 
periments by practically the same method, found that his ob- 
servers, who were all normal, usually accepted the new train 
of thought almost at once. In his experiments the first train of 
thought, on which the interruption broke, was suggested by 
the experimenter instead of being self -suggested. The whole 



136 MOVEMENT AND MENTAL IMAGERY 

attitude of the observers was therefore that of attending to 
anything that might come from the experimenter, instead of 
really allowing an associative system to get possession. 

An experiment of Poppelreuter's (112) well illustrates the 
independence of complex systems. He suggests that we take 
sentences from different stories and intermingle them, and that 
the result be read straight through from beginning to end. It 
is a fact that one will have at the end of the reading the two 
narratives side by side and each almost as clear as if it had been 
read without the other. Each system of movements has ap- 
propriated that which belonged to it, and each has in turn 
yielded place to the other. Thus we can carry on a conversa- 
tion with a fair degree of intelligence while we read a story, and 
the story ideas do not mix with the conversation ideas except 
very occasionally. 

Quite as important as the distracting effects of one move- 
ment system on another are the favorable effects of one system 
on another. One of the simplest ways in which we can make 
associative dispositions help each other is to attach some dis- 
tinguishing mark to each member in a series of movements that 
are to be formed into a successive movement system. Thus 
each member of the series becomes a simultaneous system of 
some complexity, and the various members get more individ- 
uality. A few examples will make this clear. Gordon (44) found 
that nonsense syllables could be better learned if each syllable 
was printed on a ground of different color; Peterson (107) that 
figures were better learned if they differed both in form and in 
color. The introduction of these variations increases the com- 
plexity of the material to be learned, and thus increases its dis- 
similarity: now, the less alike two movement systems are, the 
less the danger that their associates will get confused. When 
the differentiating marks are themselves connected into a sys- 
tem, the advantage they furnish is very much increased. Very 
simple illustrations of this state of things are furnished by the 
effect of rhythm in learning and the effect of associating a 
syllable with its place in the series. 



SIMULTANEOUS MOVEMENT SYSTEMS 137 

The influence of rhythm in learning has been many times 
noted in experimental studies and in everyday life: perhaps it 
was a little exaggerated in the days when schoolrooms full of 
children used to chant the multiplication table at the top of 
their voices, but it has its uses as a mnemonic factor. Ebert 
and Meumann (30) found that without rhythm, it took twenty- 
three repetitions to learn a ten-syllable series; with rhythm 
only fourteen were needed for a twelve-syllable series. Indeed, 
so strong is the innate tendency to make rhythmic all our 
motor processes whenever we possibly can, that material to be 
learned cannot be read over repeatedly without falling into 
rhythm. The attempt not to make it rhythmic operates as a 
strong distraction of attention: thus M. K. Smith (129) showed 
that when nonsense syllables are presented without rhythm, 
at irregular intervals of time, some sort of rhythm has to be 
read into them or they simply will not be learned. One reason, 
then, for the value of rhythm in the presentation of material 
to be learned is simply that we can't help making it rhythmic, 
and the attempt to do so distracts the attention. But another 
reason, and the one which concerns us at this point, lies in the 
fact that when material is presented rhythmically, the words 
or syllables are differentiated by being associated with differ- 
ences of accent, just as in Gordon's experiment they were dif- 
ferentiated by having differently colored backgrounds. Thus 
Mtiller and Schumann (91) proved that it took more repetitions 
to relearn a series of syllables in which the accented syllables 
were those which had been unaccented in the original series, 
than to relearn the original series with its accents unaltered. 
The association of a particular syllable with a particular stress 
helped to individualize it. A third reason for the advantage of 
rhythm is that it forms especially strong associative disposi- 
tions between the members of a single rhythmic foot; thus di* 
viding up the whole system to be formed into a series of smaller 
systems. That a particularly strong disposition connects the 
two syllables which belong to the same rhythmic foot was dem- 
onstrated by Mtiller and Schumann. After a series had been 



138 MOVEMENT AND MENTAL IMAGERY 

learned in trochaic rhythm, new series were presented, in some 
of which the *feet ' of the original were preserved although their 
order was altered, while in others new *feet* were made by- 
putting together a syllable that had ended one foot and the 
syllable that began the next one. The learning of the first kind 
was helped by the associations already formed between the 
syllables belonging to a single foot; that of the second kind was 
helped by the associations already formed between syllables 
which were not parts of the same foot. The results showed that 
series of the first kind were learned more quickly than those of 
the second kind; therefore, presumably, the associative dis- 
positions between syllables in the same foot are stronger than 
those between neighboring syllables in different feet. The 
exact reason for this is not so easy to make out. 

The association of each member of a successive movement 
system with its place in the series is an aid to the formation of 
the system. What constitutes the association of a particular 
part of the material to be learned with a particular place in 
the series? How do we recognize that a certain syllable came 
near the beginning of a series formerly learned, or near the mid- 
dle, or near the end? The syllables at the beginning and end of 
a series are apt to have distinguishing marks: thus, if the syl- 
lables were presented on a rotating cylinder, as is often the 
case in experiments where syllables are to be learned, the first 
and last syllables may be associated with the blank spaces at 
the beginning and end of the series. 

Vaschide (142), as long ago as 1896, made a special investi- 
gation of the process of associating an impression with its place 
in a series. He used series of eight, ten, twelve, or twenty words, 
sometimes visually and sometimes auditorily presented. A few 
seconds afterwards, the observer having first tried to recall the 
series, the words were given to him in altered order, and he had 
to assign to each its original place in the series. The localizing 
was done in various ways. Usually only the first and last words 
could be immediately placed, no doubt by some association 
with stimuli which occurred at the beginning or end of the 



SIMULTANEOUS MOVEMENT SYSTEMS 139 

series, although Vaschide implies that the placing was done 
directly and not through the aid of consciously realized asso- 
ciations. Other words were localized in groups, or by associa- 
tion with a number, or by some associative scheme such as a 
story, or forming the initials into a word; in still other cases a 
'sentiment* was the localizing mark, such as that of effort or 
difficulty connected with words in the middle, or of relief at 
nearing the end. Sometimes the marks which determined the 
place of a word were too indistinct to be analyzed; sometimes 
it was localized negatively, so to speak, as belonging, for in- 
stance, neither to the beginning nor the end and therefore nec- 
essarily to the middle. Thus in many ways an impression in a 
series can enter into simultaneous movement systems which 
stand for its place in that series. That these marks of absolute 
position form associative dispositions which aid learning a 
series of nonsense syllables was proved by Mtiller and Schu- 
mann. After having learned, on one day, four series of twelve 
syllables each, they learned next day a series in which the feet 
were those of two of the series previously learned, six feet being 
taken from each of the two, and each foot being in the position 
it had held in its original series. That is, the first foot was the 
first foot of Series I of the preceding day; the second foot was 
the second foot of Series II, the third foot the third foot of 
Series I, and so on. They also learned another series made up 
in like manner of feet from Series I and II of the day before, 
but with these feet not in the absolute position which they 
had occupied previously : thus, the first foot was the second of 
Series I, and so on. The learning of the series in which the feet 
preserved the same absolute position which they had had on 
being previously learned in a different series showed a saving of 
15% of the repetitions necessary to learn the series with the 
absolute position changed. It was not the order of the feet that 
was maintained, since the new series had feet selected from two 
different old series, but their absolute position, as at the begin- 
ning, middle, or end. Each syllable must in the first learning 
have entered into certain simultaneous movement systems. 



140 MOVEMENT AND MENTAL IMAGERY 

perhaps with the varying degrees of effort, fatigue, and relief 
characteristic of different positions in the series; and these 
must have aided the relearning with absolute position pre- 
served. Miiller and Pilzecker (90) found them so influential 
that sometimes instead of the right syllable another would be 
substituted which had nothing in common with it except the 
fact that each was, say, the fifth syllable in its series. Such as- 
sociations with absolute position are naturally, as Nagel (97) 
showed, more influential with nonsense material than with 
sense material, where the movement systems formed are so 
much more complex. 

The association of a visual object with a definite position in 
space nearly everybody will attest from personal experience 
is a help to remembering it. One recalled a certain rule in one's 
Latin grammar by thinking of its position on the lower part 
of the left-hand page. Jacobs (56) conceived the idea of trying 
the effect of a purely mental localization of visual images on 
learning: he provided a series of circles in which the observer 
was to imagine placed the nonsense syllables that were read to 
him. Such a method involves too much distraction of attention, 
and it is not surprising that it offered no advantage over sim- 
ply listening to the syllables. Gordon (44) actually presented 
the syllables in particularly striking spatial arrangements. 
They were shown either in a straight line with equal intervals, 
or in a straight line with unequal intervals, or around a circle 
w^ith equal intervals, or around a circle with unequal intervals. 
The circle with equal intervals gave the best results: the 
spatial positions of the syllables were varied enough to dis- 
tinguish them, and not so varied as to be confusing. There is 
a limit to the effectiveness of distinguishing marks added to the 
material to be learned. If the marks are too complicated, the 
formation of the movement systems which they involve may 
interfere with the formation of the new successive system which 
is the main object: too many sidewise dispositions may de- 
tract from the straight-ahead dispositions. This was clearly 
shown in Peterson's (107) experiments, where the observers 



SBIULTANEOUS MOVEMENT SYSTEMS 141 

remembered colors better if the colored objects had different 
forms, but were not helped when a size variation also was in- 
troduced. 

The best way to make simultaneous systems aid in the for- 
mation of successive systems is of course to have the auxiliary 
simultaneous systems themselves linked into a succession by 
already formed associative dispositions. This constitutes the 
enormous superiority of material that makes sense, over non- 
sense material. 'Sense' always means already formed asso- 
ciative dispositions. No matter how new an idea may be to 
us, if it has any meaning at all it evidently appeals to something 
out of our past experience. There is an overwhelming tend- 
ency to bring old and already formed movement systems into 
activity whenever new ones are to be formed. If you open the 
pages of a dictionary at random, and select any two discon- 
nected words between which to form a new associative disposi- 
tion, you have only to attend to them for a few seconds and by 
some hook or crook, some byway of past experience, you will 
find that they are already connected. Even nonsense syllables, 
selected, because of their freedom from old associations, for use 
in experiments to discover the laws under which new systems 
are formed, constantly stir up old systems. Take the syllables 
*bap' and 'dif '; almost immediately an old system springs into 
activity and one thinks, *The Baptists differ from other sects.' 
It is with the greatest difficulty that students in a psychological 
laboratory can be induced to learn nonsense syllables without 
* making sense' of them. 

These already formed systems in some cases help the forma- 
tion of a new system by breaking it up into units, each unit 
forming part of an old movement system. This process of using 
aids to the learning of nonsense material has recently been ex- 
haustively studied by Miiller (89). When the aids are simul- 
taneous systems, "apprehended by a single act of attention," 
Mtiller calls them complexes; when they are successive systems 
he calls them associative groups. All kinds of links are used in 
the formation of these subsidiary groups. Several syllables 



142 MOVEMENT AND MENTAL EMAGERY 

may be held together in a group because the first and last ones 
rhyme, or because the first and last ones have tall consonants, 
or by means of any sort of meaning association. In recall, a 
whole group will present itself as a simultaneous unity, and 
can then be turned into a successive group by having its sev- 
eral members successively attended to. But aids too have their 
disadvantages: the old systems on which they rest may some- 
times transform and falsify the material presented. Muller 
says they may cause certain elements to be neglected by atten- 
tion; moreover having too many aids at one's disposal may 
occasion hesitation, and one may sometimes reject a right syl- 
lable because one does not remember using it as an aid and 
thinks one would have done so had it been there. All this sim- 
ply means that if one sets old systems into activity, instead of 
depending on patient repetition to form the new one, the old 
systems may become so very active and so numerous that they 
interfere with one another and with the formation of the new 
system. 

When material is learned with the help of any kind of aid, 
it belongs to two or more movement systems when the learn- 
ing is complete: one, the new system which has been established, 
the others, the old systems which functioned in the learning. 
Its recall when the point of correct recitation has been reached 
is due to the combined effect of all the systems, the newly formed 
and the older ones. When a number of associative dispositions 
thus combine to produce the same result, we may use the term 
* constellation,' by Ziehen's (161) suggestion, to designate the 
process. Many times, when a disposition would be too weak 
to bring about recall unaided, it may be made the dominant 
one by the cooperation of others: the word * plant' might call 
up an image of something with stem and leaves, and set going 
other vegetable reminiscences if it did not occur in the phrase 
'manufacturing plant,' in which case we may get instead an 
image of machinery and smokestacks. Constellation is really 
the most important influence in determining recall. Even the 
action of a subliminal disposition may so aid another disposition 



SIMULTANEOUS MOVEMENT SYSTEMS 143 

as to secure its victory in a contest. This was shown by some 
curious experiments of Muller and Schumann's. Those patient 
learners committed to memory four twelve-syllable series in 
trochaic rhythm. Later, enough later for these series to have 
been partly forgotten, other series were learned which con- 
sisted of the accented syllables of the former series. Immedi- 
ately afterwards, a third set of series composed of the unac- 
cented syllables of the first set was learned, and the number of 
repetitions required to learn this third series indicated that it 
was actually helped by the previous learning of the accented 
syllables; apparently the unaccented ones had been *set in 
readiness ' by the presentation of their accented companions. 

When the material to be learned has meaning, as in the case 
of a series of words, the tendency to link the words with a con- 
nected and ready-made system through their meanings is 
irresistible unless a great effort is made to counteract it. The 
words, however randomly chosen, are made into a story. And 
when the material has connected meaning, forms a coherent 
narrative or exposition, the influence of these previously formed 
simultaneous and successive systems is so great that a single 
reading is often enough to establish the new system. The ex- 
perimental evidence that meaningful material is learned more 
readily than meaningless material is plentiful. Ogden (99) 
found sense material learned about ten times as fast as non- 
sense material, and Balaban (7) got a corresponding result; the 
latter and Radossawljewitsch (113) report that it is forgotten 
much less rapidly. The speed with which different individuals 
learn sense material is more uniform than the speed with which 
they learn nonsense material: Michotte (84) says that while 
four observers had very different capacities for the mechani- 
cal learning of pairs of words, they all four accomplished 
about the same amount of learning in a given time when they 
were instructed to think of relations between the meanings 
of the words; that is, to make use of old associative disposi- 
tions. 

An important effect of meaning associations is that they 



144 MOVEMENT AND MENTAL IMAGERY 

unify successive movement systems. We noted in the chapter 
on The Memory After-image that weak backward associative 
dispositions are formed, through the influence of the tendency 
of a movement just performed to be re-excited, between the 
second member of a successive movement system and the first. 
Now a much wider opportunity for the functioning of associa- 
tive dispositions in such an apparently reversed direction is 
given when the successive movement system is associated as 
a whole with a simultaneous system as its meaning. Thus the 
latter part of a familiar quotation can easily suggest its begin- 
ning; the words 'falling fast' may instantly call up the whole 
line, 'The shades of night were faUing fast.' When a successive 
movement system, each of whose members normally could pro- 
duce only the next following one in the series, aside from a much 
weaker tendency to produce the preceding one through the 
memory after-image process, is associated as a whole with a 
meaning, that is, a simultaneous system, the latter part of the 
successive system may suggest the meaning and the meaning 
may serve to revive the whole successive system beginning with 
its first members. This ' initial tendency in recall,' as Arnold (6) 
has called it, is due not to any reversal of the action of asso- 
ciative dispositions, but to the fact that the latter part of the 
successive series calls up the first part through the mediation of 
a simultaneous system with which the successive system as a 
whole is associated. 

The influence of meanings, that is, of old and ready formed 
movement systems, on recall will account for a difference which 
McDougall (73) regards as fundamental between two kinds of 
memory, and which he takes as a convincing proof that a 
motor theory of association is impossible, and hence that psy- 
cho-physical parallelism in general must be abandoned. Paral- 
lelism, he says, will be discredited "if it can be shown that 
habit and memory do not obey the same laws." As an argu- 
ment in support of the belief that they obey different laws, 
McDougall supposes himself to be set the task of learning a 
series of twelve nonsense syllables in a certain number of repeti- 



SIMULTANEOUS MOVEMENT SYSTEMS 145 

tions. After the learning is complete, he says, '* I can throw my 
mind back and remember any one of the twelve readings more 
or less clearly as a unique event in my past history. I can 
remember perhaps that during the fifth reading I began to de- 
spair of ever learning the series, that I made a new effort, that 
someone spoke in the adjoining room and disturbed me dis- 
agreeably; I may perhaps remember what he said." **If the 
repetition by heart of the nonsense syllables and the remember- 
ing of any one of the readings of the series are both to be called 
evidences of memory, it must be admitted that two very dif- 
ferent functions, two very different modes of retention, are 
denoted by the same word." 

The chief differences between them he states to be the fol- 
lowing: — 

(1) The syllable learning involves the formation of a habit 
to which each repetition contributes a little; the recall of the 
events which characterized a single repetition "depends wholly 
on a single act of apprehension." The reason for this, we should 
say, is simply that the syllable learning involved the formation 
of a wholly new movement system, while the events of a single 
repetition are already related to many old movement systems; 
in other words, they have meaning. We have often before felt 
weary and discouraged when half way through a task; we have 
been interrupted and have felt annoyed on many previous oc- 
casions. These happenings are so readily recalled because they 
are relevant, and to be relevant means to be already imbedded 
in the same movement systems. 

(2) Reproducing the syllables involves a forward-looking 
attitude; recalling a particular repetition involves a backward- 
looking attitude. To this we should agree; it is immediately 
related to the next point of difference. 

(3) Recalling the syllables is not helped by any effort to cast 
back thought to the moment of apprehension; recalling a 
particular repetition is aided by "voluntary rummaging in the 
past," Naturally, we should answer, since the syllables form 
a wholly new movement system, and the memory of a partic- 



146 MOVEMENT AND MENTAL BIAGERY 

ular repetition is as we have seen largely interwoven with older 
systems. 

(4) The syllable learning involves the connecting of eight 
simple impressions only, yet it requires twelve or more repeti- 
tions: the remembrance of a particular event involves a very 
complex set of impressions, yet it depends only on a single act 
of apprehension. Naturally, because it is aided by the old 
movement systems of meanings. 

(5) The series is quickly forgotten; the particular event may 
be recalled for a long time. Naturally, for the same reason that 
meaningful material may be longer retained. 

Another instance of the effect of auxiliary movement sys- 
tems is furnished by the location that is assigned to visual 
imagery. There seem to be two sources from which the sys- 
tems are derived on which such localization is based. One is the 
actual surroundings of the individual at the moment; the other 
is what he recalls of the actual location of the real object that 
is being imaged. Milhaud (85) reports that some observers 
localize the mental image of an object with reference to their 
own position at the time, while others feel themselves trans- 
ported to the real position of the object represented : the differ- 
ence, he suggests, is due to the fact that observers of the former 
type are more interested in their own kinsesthetic sensations 
and cannot lose the sense of their actual position. Martin (75) 
enumerates no fewer than twelve different ways in which a 
mental image may be located, and a great variety of condi- 
tions which determine the localization, all of which, however, 
seem to fall into two general classes, namely, those due to 
actually present objects and the position of the observer's body, 
and those connected with the memory image itself, such as the 
recollection of having last seen the original object in a partic- 
ular situation. 

The distinction drawn by Perky (106) between a memory 
image and an image of imagination is based on a difference in 
the complexity of the movement systems involved. Perky 
caused the persons she experimented on, sitting in a dark room 



SIMULTANEOUS MOVEMENT SYSTEMS 147 

with one eye closed, to call up what she called a memory image 
and an imaginary image of the same object. By a memory 
image she meant the image, say, of a particular horse recently 
seen; by an imaginary image she meant the image of a horse 
not connected with any particular occasion of past experience. 
This use of the terms memory and imagination may have his- 
torical justification, but it is surely not the ordinary one. Imag- 
ination forms new combinations out of past experiences: one 
may imagine a centaur, but one has to remember a horse, and 
one remembers, not imagines, it, whether it is thought of as 
wath or without a context. Baldwin and Stout, in the former's 
** Dictionary of Philosophy and Psychology," say of the term 
* imagination': "It seems better to adopt the current usage of 
popular language, and to restrict the term to that forming of 
new combinations which is made possible by the absence of ob- 
jective limitations confining the flow of ideas." Perky found 
that the * memory images ' of her observers required more eye- 
movement and more kinsesthesis generally, than their * imagi- 
nation images'; also that "in imagination consciousness is 
narrowed and there is inhibition of irrelevant associations, 
while in memory attention wanders and the image is unstable." 
This is what we should expect: if an observer is required to 
call up, besides what we should call the memory image of 
an object, memory images of its surroundings and attendant 
circumstances on a particular occasion, the motor systems will 
naturally be more complicated than when the object is re- 
called alone. 

Finally, a profound influence is exerted by old movement 
systems upon new ones in the processes which underlie the 
alteration of memory images with time. It may be laid down 
as a law that whenever in a movement system it is possible for 
an old associative disposition, based on much repetition, to 
take the place of a new one whose strength lies rather in re- 
cency than in repetition, the substitution occurs. This is of 
course precisely the fundamental law of perception. If the 
third and fourth fingers are crossed, and a pencil is laid be- 



148 MOVEMENT AND MENTAL IMAGERY 

tween them, the patient's eyes being closed, he will have ex- 
cited the tentative movements that belong to two pencils 
rather than those belonging to one, even though he knows 
there is only one pencil: the associative dispositions recently 
set up by the sight of the single pencil are not able to withstand 
the old dispositions connected for life with the stimulation of 
two points on the skin that are not normally reached by a 
single object at the same time. On this tendency of old dis- 
positions to supplant new ones is based the tendency of memory 
images to alter in the direction of the ordinary and normal ex- 
perience; to lose their peculiar and unusual features. Thus War- 
ren and Shaw (14S) found indications that the memory image 
of a large square tends to grow smaller and that of a small 
square to grow larger, both being as it were attracted towards 
a mean. Leuba (69) aiTdXewis (71), working by entirely dif- 
ferent methods, noted a tendency in the memory image of a 
bright light to grow dimmer and that of a dim light to grow 
brighter, or rather to be judged as the image of a brighter light 
than that which had actually produced it. Phillippe (109), who 
had his observers look at a collection of five small objects and 
then draw them from memory after various intervals of time, 
reports that the images "seem to tend towards a type pre- 
existing in the mind" which exerts an attraction: thus the 
features on a Japanese mask tended in the memory image to 
resemble the European type. Kuhlmann (64) says that the 
memory images of the picture of an object tend towards rep- 
resenting the object itself, which of course involves older move- 
ment systems than those of the picture. Some time ago I saw 
at an exhibition of the National Academy of Design Waugh's 
painting called "The Knight of the Holy Grail." I remember 
that the parts of the picture which impressed me most were the 
sky, with a single faint star and the line of mountains under- 
neath, the red glow of the Grail, and the very faint halo around 
the Grail. A stanza from Tennyson's poem was inscribed on 
the frame, and the last line, "And starlike mingled with the 
stars," ran in my mind, *perseverated,' for several days after. 



SIMULTANEOUS MOVEMENT SYSTEMS 149 

which probably accounts for the persistence of the memory 
image of the sky and the Grail. For this is the part of the pic- 
ture which is now clear in my memory; next come the figures 
of the angels, while the figure of Galahad I can scarcely get 
at all. When I attend to the angel figures, I see them grouped 
around the Grail in a way that I know must be incorrect, be- 
cause it is inconsistent with my image of the Grail seen against 
the sky. I think this wrong grouping of the angels has been 
borrow^ed from another picture in which the angels are carrying 
a little child: I have a vague tendency to complete the angel 
group in this way. As I let my attention dwell on the angels, 
suddenly the image of a mast at the bow of the boat appears, 
at first with an air of authority about it; but presently I reject 
it. I do not believe it was in the picture: some other boat pic- 
ture has * contaminated,' as the philologists say, the Galahad 
one. I now fix my attention on the figure of Galahad. I see 
him in profile, kneeling, with hands pressed together in the con- 
ventional attitude of prayer. His face is like that of the Gala- 
had in the Abbey pictures. Now, in order to test the accuracy 
of the memory image which I have thus called up and devel- 
oped, I can fortunately appeal to an illustrated catalogue of 
the exhibition. I find that the mountains are much higher and 
wilder in the real picture than they were in my memory image; 
that instead of there being a group of two or three angels at the 
same level, there are two pairs, one above the other, an angel 
of the upper pair holding the Grail against the sky; that the 
figure of Galahad is not kneeling but sitting, though with the 
hands folded in prayer as I had remembered them; that my 
memory image had placed him near the centre of the picture 
instead of at the extreme left where he really is, and finally that 
the lower pair of angels carry in their hands tall wax candles in 
still taller candlesticks. It occurs to me that these candlesticks 
are responsible for my picture of the mast at the bow of the 
boat. There is no mast. My rejection of the mast image when 
it presented itself was accompanied by the incipient, unde- 
veloped thought that a mast in that position would spoil the 



150 MOVEMENT AND MENTAL IMAGERY 

picture. Was it perhaps not the long, straight, nearly vertical 
lines of the candlesticks in the bow that suggested a mast? 
Now, almost all the errors in my memory image are in the di- 
rection of making it more commonplace, more generic. The 
rugged wildness of the mountains was softened; the unusual 
distribution of the angel figures became the more familiar image 
of two or three figures at the same level, and tended to blend 
with other pictures of the same general kind, as is shown by the 
intrusion of the child's figure. The figure of Galahad was 
shifted towards the centre to make the composition more com- 
monplacely symmetrical; the correct image of the hands 
pressed together suggested the ordinary accompaniment of a 
kneeling rather than a sitting figure. Finally, the candlesticks 
were so unusual a feature of the bow of a boat that they trans- 
formed themselves into a mast. 



CHAPTER VIII 

THE PROBLEM OR PURPOSE 

In the preceding chapter we have considered some of the 
ways in which movement systems may interact with each 
other, and associative dispositions, the tendencies of one move- 
ment to excite another, may influence one another when they 
are simultaneously set into action. Upon such mutual influ- 
ences the wandering of our thoughts at random, the play of 
fancy, depends. But much of our thinking is not random; it is, 
rather, directed toward a definite end. Is it possible to explain 
directed, controlled, purposeful thought, without introducing 
any new principles and laws beyond those which govern the 
mutual relations of associative dispositions? 

Psychologists in the last few years have been much occupied 
with this subject of the exact nature of the problem or pur- 
pose, as directing the course of mental phenomena. It was 
Watt (148) who in 1905 first used in the sense which has re- 
cently become technical the German word 'Aufgabe^* to indi- 
cate the idea of a problem to be solved, as affecting the asso- 
ciative dispositions that follow upon its acceptance. The term 
was used in the same year by Ach (2) to designate certain fea- 
tures of the reaction experiment. For instance, it has long been 
customary to distinguish in such experiments between the 
sensorial reaction and the muscular reaction: in the former the 
reagent's attention is beforehand directed towards the stimulus, 
which he is instructed to expect and to discriminate accu- 
rately when it occurs; in the latter his attention is directed be- 
forehand wholly towards the movement that he is to make when 
the stimulus occurs. Ach pointed out that this is a difference 
in the problem, the Aufgdbe^ which in the sensorial reaction 
is, "React when the stimulus is fully apprehended," and in 
the muscular reaction is, "React as quickly as possible." The 



152 MOVEMENT AND MENTAL IMAGERY 

influence of the problem, once attended to, upon subsequent 
associative dispositions and movements Ach explained by- 
saying that to associative dispositions and perseverative dis- 
positions we must add a third kind of disposition in the ner- 
vous system, namely, determining dispositions or tendencies. 
A determining tendency proceeds from the idea of an end, and 
is responsible for the fact that the same stimulus may suggest 
different ideas under the influence of different problems. The 
strength of determining tendencies differs with individuals; it 
is modified by opposing associative and perseverative tend- 
encies. An ingenious method of measuring the strength of cer- 
tain determining tendencies was devised by Ach and has 
already been mentioned.^ Associative dispositions between 
certain syllables were formed by a number of repetitions of the 
syllables. The observer was then given certain syllables of the 
series as stimuli, having been previously instructed that in- 
stead of responding by the next syllable of the series he was to 
give a new syllable that rhymed with the stimulus syllable. 
That is, he was to overcome an associative disposition by 
means of a determining tendency proceeding from his instruc- 
tions. If he failed to carry out the instruction, and simply gave 
the syllable associated with the stimulus in the series learned, 
then the determining tendency was too weak to overcome the 
associative disposition. The strength of the associative dis- 
position was measured by the number of repetitions used to 
form it, and the strength of a determining tendency could be 
measured by the number of repetitions needed to found an 
associative disposition that just overcame the determining 
tendency. 

The question for us is evidently, 'What is the physiological 
basis of determining tendencies?' If associative tendencies 
or dispositions are based on lowered synaptic resistances be- 
tween the kinsesthetic centres excited by the performance, 
either tentative or full, of one movement and the motor centre 
belonging to another movement, upon what are determining 

1 See page 95. 



THE PROBLEM OR PURPOSE 153 

tendencies based? And a necessary step towards the solution 
of this question is as evidently a consideration of what con- 
stitutes a problem idea. 

It would seem that the distinguishing characteristic of a 
problem idea, which differentiates it from other kinds of ideas, 
is the persistence of its influence. In disordered revery, we fly 
from one thought to another: each thought is responsible for 
the occurrence of the next, but beyond the next its influence 
hardly reaches, except occasionally. Thus we find at the end of 
our train of fancy that we have reached a conclusion we never 
anticipated: we started with the thought of the European war 
and we have arrived at a mental picture of a barn where we 
hunted for eggs in our childhood. A problem idea, on the other 
hand, exerts its influence often for a very long time: the prob- 
lems connected with writing a book pursue us for months and 
years. 

The degree of persistence required of a problem idea's in- 
fluence of course varies within wide limits. The shortest dura- 
tion of such influence is demanded when the problem is simply 
that of attending to a particular aspect of a stimulus about to 
be given. If an observer is told to notice especially the color 
of a design that is to be placed before him, the influence of this 
problem or task need persist only a few seconds. If all prob- 
lems could be solved so quickly, we might need nothing but the 
memory after-image to explain their influence. As a matter of 
fact, Groos (45) in 1902 suggested that what he called the 
* after -function' or * secondary function' of nervous elements 
accounts for the difference between ordered thought and rev- 
ery, and prevents us from being always the sport of wandering 
ideas. His pupil Schsefer (121) undertook to measure the 
strength of a person's secondary functions as a general individ- 
ual characteristic, by calling out a stimulus word and requiring 
the observer to write all the words he thought of during one 
minute. The number of times the observer broke away from 
the influence of the starting word was taken as a measure of 
the strength of that word's after-effect. But the secondary 



154 MOVEMENT AND MENTAL IMAGERY 

function, or the memory after-image, is something that be- 
longs to ideas whether they are problem ideas or not: for in- 
stance, Schaefer finds that ideas with emotional suggestion 
have much stronger secondary functions than ideas without it. 
If it is said that problem ideas have stronger secondary func- 
tions than ideas that are not problems, the question remains as 
to the reason for this difference; and besides, the conception 
of the secondary function or memory after-image process as 
the source of a problem idea's persistent influence would hold 
only for very short-lived problems. One could not explain the 
hold of a complicated mathematical difficulty on the mind, 
whereby it works itself out through months of labor, by any- 
thing so fleeting as the secondary function of the original put- 
ting of the question. 

Muller (89) and Offner (98) both think that the persistent 
influence of the problem idea is to be explained by 'persevera- 
tion. It has a spontaneous tendency to recur to the mind, 
through considerable intervals of time, and not merely im- 
mediately after it has first been attended to. But obviously the 
point to be explained is why problem ideas as such have this 
perseverative tendency. It is not as uncertain an affair as the 
perseverative tendency of a tune which * happens' to run in 
one's head: the human mind would be a very inefficient in- 
strument if its plans and piu*poses had as fitful a tendency to 
recur and persist in their influence as the perseverative tend- 
ency of a tune. What is it that gives the problem idea such an 
especially good chance of recurring and persisting? Watt (148) 
said that the problem idea was simply a greater and stronger 
'reproduction motive' than other ideas, and that he did not 
know its physiological basis. Muller appears to think that its 
relatively permanent influence is due to a combination of asso- 
ciative tendencies; to * constellation.' That is, the problem idea 
is one which starts into action a movement system so com- 
plicated that it naturally takes some time to work itself out. 
The activity of such a system has a strong tendency to recur. 
This conception seems to apply well enough to certain kinds 



THE PROBLEM OR PURPOSE 155 

of problems, but not so well to others. It describes the case of 
a problem which like a complicated mathematical theorem has 
to be developed step by step, but not the case of the addition 
of a long column of figures : here the associative system is not 
complicated at all. The same simple kind of association has to 
be made to each of the figures in the column and the one before: 
the constellation involves only three factors, the two num- 
bers and the problem of their sum. If we say that the perform- 
ance of such a task as this is due simply to the persistent after- 
effect of the preceding step in the addition, to the fact that, as 
it were, we get in the habit of adding, that adding runs in our 
head, we evidently do injustice to the steady purpose that is in 
our mind. We do not add because we have got into the habit of 
adding, simply, but because we formed the * resolution ' at the 
outset to add. In this * resolution' something more than ordi- 
nary associative processes, whether simple or complicated, and 
something more than the perseveration of associative proc- 
esses, seems to be at work. Thus we find several authorities 
implying that there is an affective or emotional aspect to the 
problem idea. Claparede (22) declares that logical thought is 
distinguished by the presence of a "sentiment of the end." 
Meumann (81, 82) says that the capacity of fixing attention on 
the idea of the end is connected with affective life, and has 
developed this conception most ably in his "Intelligenz und 
WiUe." 

We shall take it for granted that the most essential thing 
about a problem idea, as distinguished from other ideas, is the 
persistence of its influence, and that to explain this persistence 
we need to invoke something over and above ordinary associa- 
tive dispositions: in other words, that an associative tendency 
becomes a determining tendency through the operation of 
some factor that is not itself an ordinary associative tendency. 

Let us take a very simple case of the operation of a problem 
idea, that where a person is instructed to direct his attention 
towards a particular aspect, say, the color, of an impression 
that is to be given him, and to note whether the impression 



156 MOVEMENT AND MENTAL EMAGERY 

contains a particular color, red. Now, according to our gen- 
eral theory, the words of the instruction set up the tentative 
movements belonging to the color red. These tentative move- 
ments, however, are not set up merely for an instant, but per- 
sist until the impression to be judged is actually given; or if 
they lapse momentarily, when there is a long wait between the 
giving of the instructions and the presentation of the im- 
pression, they renew themselves spontaneously. We may call 
tentative movements which thus endure and recur, persistent 
tentative movements. I think we shall find that they are char- 
acteristic of all cases where a problem idea is operative; of all 
cases, that is, where mental processes are directed and not 
random. 

If we pass from this very simple problem to the considera- 
tion of complexer problems, we shall find it convenient to divide 
them into two classes. In one class of problems, we have to do 
with what we have called * sets of movements ' ; in the other class 
with what we have called * systems of movements.' In a set of 
movements, it will be remembered, a number of different move- 
ments are associated, each in the same way, with one and the 
same movement. For instance, all the names of colors are 
associated with the same word, namely, * color.' The word 
* color ' will call up any or all of the particular color names, such 
as *red,' * green,' *blue.' These names have no connection with 
each other except through the common name color or through 
other common features: there is no necessity that when one 
thinks of red one should also think of blue or of green unless the 
movements belonging to color in general are exerting an influ- 
ence. In a set of movements, the movement associated with 
all the members of the set is like the string tied around a bundle 
of straws: without the string, there is no unity. Now in a 
movement system, on the other hand, the movements are 
linked among themselves, either in simultaneous or in suc- 
cessive systems. For instance, many persons know the names of 
the colors in their spectral order: violet, indigo, blue, green, 
yellow, orange, red. Such a series of words is a movement 



THE PROBLEM OR PURPOSE 157 

system: the performance of one movement leads directly to the 
performance of another, and so on. 

A simple illustration of a problem that involves sets of 
movements rather than systems of movements would be the 
case where a person is instructed to observe the color of a pic- 
ture to be shown him. He is not told to look out for a particular 
color, but just to note what color or colors may be present. The 
persistent tentative movements belonging to 'color' tend to 
excite all the motor centres connected with particular colors: 
many of these movements are incompatible, of course, so they 
cannot be actually executed at the same time, even as tentative 
movements, but they may be excited in rapid succession and 
thus all be in a state to recur readily when the colors of the 
impression to be judged actually appear. 

Again, suppose a person is put to adding a column of figures. 
The word * add ' similarly places in readiness a set of tentative 
movements, those connected with the adding process: for in- 
stance the words ' two and three are five,' * three and seven are 
ten.* Or suppose that the task is one that is familiar in the 
psychological laboratory : suppose a series of words is given to 
an observer with the instruction that he is to react to each word 
by giving the word expressing the opposite idea. To *high ' he is 
to respond *low,' to * short,' *long,' and so on. Here, too, evi- 
dently, the persistent movements connected with the word 
'opposite' put in readiness the motor responses connected with 
a whole set of opposite words. 

On the other hand, perhaps the simplest illustration of a 
problem idea which involves a system of movements rather 
than a set of movements is the effort to recall a forgotten name. 
Here one usually tries to reinstate entire situations in which the 
name was formerly experienced; that is, one tries to recall a 
whole context, and the parts of the context are linked with each 
other in the interdependent fashion of movement systems. Of 
course, one may try to get the name by reconstructing several 
situations in which the only common element was the name in 
question: in such a case the systems themselves form a set of 



158 MOVEMENT AND MENTAL IMAGERY 

movements; but each situation is itself of the nature of a move- 
ment system. The persistent tentative movements are those of 
the system, and * constellation,' or the operation of simultane- 
ous systems, is the best means of effecting recollection. The 
process is the same, only more complicated, in the highest 
operations of creative thought. When the inventor solves his 
problem, he does so through the persistent influence of certain 
tentative movements that set in activity whole systems of 
movements : each step of his reasoning is dependent, not only 
on the step immediately before it, but upon the whole series 
that has preceded. Upon the power of forming such very com- 
plicated movement systems creative power rests in part; but 
also on the power of sticking to one's problem until one has 
got it solved. This latter capacity relates, evidently, to the 
same character of persistence in the influences set at work by 
the problem idea. 

Persistent tentative movements, then, are characteristic of 
the problem idea. Whence do they get their persistence? 
Partly from perseveration and the memory after-image, but 
largely from another source. 

In the chapter on types of association between movements, 
we distinguished movement systems as phasic and static. The 
former are simply complex movements, requiring the coopera- 
tion of a number of innervations. The latter are not movements 
but attitudes, that is, what is required in them is the steady 
maintenance of innervation. Holding up the head is a static 
movement system: it requires not only the simultaneous but 
the continued innervation of a whole set of muscles. In such 
cases, as Sherrington has pointed out (126, pages 338-39), the 
stimuli to the continued innervation of the muscles are the 
kinsesthetic excitations resulting from the innervation of the 
other muscles in the system, and these kinsesthetic or * pro- 
prioceptive' excitations, instead of ceasing to be effective as 
stimuli according to the law of sensory adaptation by which 
the effectiveness of a long-continued stimulus is reduced, seem 
to be able to preserve their influence unimpaired for long peri- 



THE PROBLEM OR PURPOSE 159 

ods of time. Two causes, in fact, limit the duration of a static 
movement system. The first is fatigue. The second is the occur- 
rence of a stimulus which demands of the organism a motor re- 
sponse prepotent, that is, having by inherited arrangement the 
right of way, over the motor innervations involved in the static 
system. In the case of those typical static movement systems, 
the external bodily postures, such as standing or sitting erect, 
a stimulus leading to actual movement always tends to be 
prepotent over the static system stimuli. An internal static 
movement system, not involving the muscles of locomotion, 
would be less liable to interruption from prepotent stimuli. If 
an internal static movement system, relatively permanent by 
virtue of its essential character, can be associated with any 
other motor excitation, it would have the effect of making the 
latter persistent, and constantly tending to renew it. In other 
words, if the motor excitation on which an idea is based can be 
associated vnth an internal static movement system, it will acquire 
the persistence needed to transform the idea into a problem idea. 

Now, what happens at the critical moment when an idea is 
adopted as a problem idea? What, in other words, is the nature 
of a resolve? What is the difference between merely having the 
idea of an act occur to one, and deciding that the act shall be 
carried out? 

According to Ach (3) the adoption of a purpose, — that is, 
the making of a resolve, — which constitutes the difference 
between the directing or problem idea and an ordinary idea, is 
characterized by four factors, which he terms the image mo- 
ment, the objective moment, the actual moment, and the 
zustdndliche moment, a term that is difficult to translate, but 
may perhaps be appropriately rendered as * affective moment.' 
The image moment consists of strain sensations. The objective 
moment, which may also, rather confusingly, consist of an 
image, is the idea of the end, and of the means, oftenest verbal, 
sometimes merely an awareness.^ The actual moment involves 
an activity of the self. The I-side of the psychic process be- 
* See page 191. 



160 MOVEMENT AND MENTAL IMAGERY 

comes prominent in quite a different way than is the case in 
other experiences, and in the moment where the wiil-act is 
present in its energetic form, a uniquely determined change in 
the state of the I is experienced. Moreover, this consciousness 
of the activity of the self involves not merely an *I will,' but an 
*I really will,' which excludes every other possibility. Finally, 
the affective moment consists of a conscious attitude of effort. 
What relation this bears to the strain sensations which formed 
the image moment is not stated, but we may suppose that the 
difference is simply that the conscious attitude of effort is 
unanalyzable, and not to be located as strain sensations are. 

It will be seen that the actual moment introduces a factor 
which cannot be reduced to sensation, image, or affection. The 
discovery of this factor rests simply upon Ach's interpretation of 
the introspections of his observers. No suggestion as to the pos- 
sible psychophysical basis of this activity of the self is offered. 

Meumann's (82) analysis of the resolve also introduces, or 
discovers, a unique factor. For Ach's actual moment, he sub- 
stitutes a process of inner assent to the end of the action. Be- 
sides the idea of the end and of the means of reaching it, we 
judge this end and give our assent to it. Moreover, and this is 
an addition to Ach's actual moment, we must be conscious that 
this inner assent is the real cause of the voluntary act; that 
without the assent the act would not be performed. The inner 
assent is the symptomatic manifestation of "an elementary 
active reaction of the Ego." Again we are left wholly without 
any clue as to the physiological process involved. 

The fact is that in order for an idea to be accepted as a prob- 
lem idea, and in consequence to obtain relatively lasting in- 
fluence upon associative processes, it has in ordinary language to 
appeal to a need, a desire. All desires are ultimately connected 
with the great motor outlets of instincts. If we examine in- 
trospectively what happens when an idea 'arouses a desire' 
that cannot immediately be gratified, we find, I think, that 
motor effects of either or both of two different kinds are pro- 
duced. The one effect (not necessarily first in time) is that we 



THE PROBLEM OR PURPOSE 161 

*feel restless/ * uneasy.' The restlessness seems to be pro- 
duced by diffused and shifting motor innervations, which ap- 
parently have no usefid connection with each other, and seem 
rather to be the effects of a common cause than to form a true 
movement system. The other effect that may be connected with 
the arousal of desire I shall call the activity attitude. In its 
intenser degrees it is revealed to introspection as the * feeling of 
effort/ which is recognized as the accompaniment of active 
attention. Introspection further indicates that it is not due to 
shifting innervations, but rather to a steady and persistent set 
of innervations. It appears from introspection, also, to be in 
its intenser forms a bodily attitude, involving a kind of tense 
quietness, a quietness due not to relaxation but to a system of 
static innervations. We should then class it under the head of 
* static movement systems.' 

The writer would like to suggest that a problem idea becomes 
the starting-point of effective and directed thought towards its 
solution only when the incipient motor innervation which the 
problem involves connects itself, not simply with general rest- 
lessness and uneasiness, but with the steady innervations of the 
activity attitude. Through their inherent and characteristic 
persistence, as members of a static movement system, the 
problem innervation is kept from lapsing and may continue 
to exert an influence upon associated motor innervations and 
to arouse imagery which bears on its solution. 

We must, indeed, if such a view be accepted, go a step beyond 
introspection. The * feeling of effort,' the form in which the 
activity attitude reveals itself most clearly to introspection, is 
connected not with smooth and easy thinking but with inter- 
ruptions and obstacles to the course of thought. If such ob- 
stacles are insurmountable, the activity attitude either resolves 
itself into the shifting movements of restless desire, or drops 
into an attitude of relaxation. But if the obstacle is successfully 
surmounted, the activity attitude, we must suppose, does not 
cease because it is less evident to introspection, but is most 
effective in securing the persistent influence of the Aufgabe 



162 MOVEMENT AND MENTAL IMAGERY 

when the kinsesthetic sensations to which the activity attitude 
itself gives rise are not themselves the objects of attention. 
In fact, just in proportion as it is evident to introspection, that 
is, attended to for its own sake, it is less effective in securing 
the persistence of the problem system. Is this only another 
way of saying that thinking implies active attention and that 
active attention is characterized by the presence of the con- 
sciousness of effort, or the feeling of activity .^^ Yes; but it is 
saying more: namely, that the naotor innervations underlying 
the 'consciousness of effort' are not mere accompaniments of 
directed thought, but an essential part of the cause of directed 
thought. It is the static, mutually reinforcing innervations of 
an organized movement system which, associating themselves 
with the incipient innervation set up in connection with the 
problem idea, keep that excitation effective and prevent it from 
lapsing. What is required to transform an idea into a problem 
idea or Aufgabe is the association of the incipient motor excita- 
tion which it involves with some excitation relatively static and 
enduring in its nature. And a determining tendency is an asso- 
ciative disposition one of whose exciting influences is the activity 
attitude. 

All students of the learning process report the great influence 
of effort, the 'determination to improve.' Thus Bryan and 
Harter (17) say, "It is intense effort that educates"; Johnson 
(58) ascribes plateaus or periods of no improvement in the learn- 
ing to pauses in the effort, and Book (13) says that "less effort 
was actually put into the work at all those stages of practice 
where little or no improvement was made." Now the actual 
causative influence of effort on learning has usually been re- 
garded as due to a more or less mysterious will process, of 
which the bodily attitude characteristic of activity or effort was 
merely the accompaniment. The theory here suggested is the 
first, so far as I know, to explain how a bodily attitude like that 
of effort can actually be the cause of improved mental work, 
by prolonging, through its own persistent nature, the influ- 
ence of the problem on associative processes. 



THE PROBLEM OR PURPOSE 163 

In the section on "The Effect of Repetition on the Strength 
of Associative Dispositions," we left unexplained the fact that 
in learning a series of words or nonsense syllables, a recitation 
from memory does much more to strengthen the associative 
dispositions which it brings into play than a new presentation 
or reading of the series. The reason for this difference would be 
found, we said, in the different attitudes involved in reciting 
from memory and merely reading. Following a suggestion from 
Katzaroff, we find that it is in fact the activity attitude that is, 
in large measure at least, responsible for the great value of 
recitations in memorizing. "In the readings," Katzaroff says 
(61, page 257), "the subject is passive, calm, indifferent; in the 
recitations he is active, he has to seek, he rejoices when he has 
found and gets irritated at the syllables which evade his call. 
Hence a crowd of sentiments of affection for certain syllables, 
of antipathy for others, which contribute to enrich the asso- 
ciative nexus and favor conservation and reproduction. . . . 
When a pupil has read a fable many times without ever reciting 
it, he is thrown off the track when he has to say it by heart be- 
fore the teacher: the active attitude in which he finds himself 
at the moment of the recitation, being different from the pas- 
sive attitude in which he found himself at the time of the read- 
ing, is an obstacle to the revival of his memories." There can 
be no doubt that while one may not be wholly passive during 
the reading of a series to be memorized, one has much less of 
the activity attitude than during the effort to recite. Thus an 
attempted recitation forms an association between the series 
as a whole and the attitude of activity, which is of the utmost 
value when the final recitation is made that is the test of the 
learning: while a mere reading forms such an association either 
not at all or in a much less degree. 

On this theory it is possible to explain, or at least to find a 
plausible description of, certain individual variations in the 
effectiveness of directed thought. The activity attitude, we 
may suppose, will not ordinarily be set up in connection with 
an idea that does not, directly or indirectly, appeal to some 



164 MOVEMENT AND MENTAL IMAGERY 

instinct. An idea that does so appeal may stir up merely a 
state of unrest, involving diffuse and shifting innervations. In 
certain individuals, this is the common result. Owing to causes 
lying in his physiological constitution and not accessible to his 
consciousness, ideas in such a person habitually set up unrest 
rather than activity attitudes: they come 

*' Close enough to stir Ms braia 
And to vex his heart in vain.''' 

In other natures, unrest quickly yields place to the fruitful 
and useful attitude of activity; while still others are so phleg- 
matic that even those ideas whose connection with instinctive 
outlets is fairly close wiQ not so much as stimulate to unrest. 

In the same individual, readiness to assume unrest attitudes 
and the activity attitude varies from day to day. Our physi- 
ological condition determines the intensity of instinctive ap- 
peals: where these are weak, both unrest and activity atti- 
tudes will fail to be aroused. A constant crux of discussion has 
been the lack of correlation between unrest and the activity 
attitude. In debates on the determination of the will, the 
* strength of motives' has commonly referred to the intensity of 
the unrest set up by certain ideas. And it has often been pointed 
out that we sometimes act on a motive weaker than that which 
at another time fails to move us to action. Hence the illusion 
that we act without a cause; that will is not determined by the 
strongest motive. The facts, in my opinion, are as follows. Our 
physiological condition at certain times is unfavorable to the 
production of the activity attitude. The instincts may be alive: 
the motor pathways connected with them may be ready for 
use. The unrest aroused by an idea indirectly connected with an 
instinctive outlet may be intense. But the activity attitude is 
not assumed; and if the idea's connection with the instinctive 
outlet be so indirect that 'thinking' is necessary to willing, then 
the 'wiir is lacking despite the strength of motive. Since no 
introspection can certainly determine whether the organism is 
or is not in the proper physiological state for the assumption of 



THE PROBLEM OR PURPOSE 165 

the activity attitude, the relation of motive and will is uncer- 
tain, contingent. At another time an idea that stirs up a far 
weaker unrest attitude may give rise to the attitude of activity 
and so dominate associative processes to a successful working 
out of its problem. 

The question naturally occurs as to how on this theory the 
influence of a particular problem idea is terminated. Obvi- 
ously we stop mental work on a problem under two conditions: 
when the problem is solved and when it is not. If a problem 
reaches its solution, the persistent tentative motor processes 
find their fulfillment. The result is of course that if the prob- 
lem idea is later suggested, there will be no suspension of the 
motor processes, but the passage to the solution wdll be im- 
mediate: only if the solution has been forgotten, through the 
effect of time in heightening resistances at synapses, will the 
motor innervation remain obstructed, and if conditions are 
favorable, the activity attitude will come into function and the 
problem be worked through again. 

But a problem is often dropped without having reached a 
solution. And the dropping may be temporary or final. A 
problem that requires a long train of thought for its solving is 
usually dropped and resumed several times before it is finally 
worked out, if it ever is. On our theory, the interruption of 
mental work on a problem before the solution is reached must 
be due to relaxation of the activity attitude. The usual causes 
bringing about such a relaxation are (1) the occurrence of a 
prepotent stimulus demanding an entire shift of attitude (the 
dinner-bell calling the thinker to food), or (2) fatigue. Really 
the second is but a special case of the first, since the stimuli 
produced by fatigue are prepotent when they reach a certain 
degree of intensity. 

The relaxing of the activity attitude, and consequent inter- 
ruption of directed thought on a given problem, may be fol- 
lowed after an interval by the resumption of active work on the 
task. Judging from introspection, such a resumption may be 
started either by the associative suggestion of the problem to 



166 MOVEIMENT AND MENTAL IMAGERY 

our minds once more, or by the 'spontaneous* or perse verative 
recurrence of the activity attitude itself, which recalls the 
problem. We resume our task either because some other idea or 
something in our surroundings recalls the task to our minds and 
the task sets up the activity attitude; or because we 'feel like 
work,' and casting about for something to work at, we find that 
the activity attitude, thus recurring 'spontaneously,' suggests 
either the task most recently associated with it, or the task 
which the context and surroundings combine to suggest. If the 
activity attitude recurs when I enter my study, the unfinished 
task it suggests is that which belongs to those surroundings; if 
it recurs in the laboratory, it sets in excitation the centres con- 
nected with my unfinished laboratory tasks. This spontaneous 
recurrence or perseveration is familiar in the case of organic 
movements such as desires or regrets: it often happens that we 
have in consciousness first the 'awareness' of wanting some- 
thing, or that something pleasant or unpleasant has happened, 
and these recurring motor states call up the idea of their own 
cause. We remember in a few moments what it was that we 
wanted, or that pleased or displeased us. 

The experience of extreme unpleasantness in connection with 
any problem seems to break the connection between the incip- 
ient motor innervations connected with that problem and the 
activity attitude. A special and practically very important 
case of this occurs when work on the problem has been pushed 
to the point of great fatigue. The fatigue of mental work is 
rather generally acknowledged to be essentially the same as 
that resulting from physical work. We may assume that it is 
fatigue induced by too long continuance of the activity at- 
titude. The worker has dropped his uncompleted task because 
the fatigue poisons, acting as prepotent stimuli, compel an 
interruption of the activity attitude. If the fatigue is moderate 
in amount, an attitude of relaxation supplants the attitude 
of activity. But if the fatigue is great, the stimuli which it 
produces give rise not merely to an attitude of relaxation 
but to the general negative response accompanying marked 



THE PROBLEM OR PURPOSE 167 

unpleasantness. The negative response, as many phenomena 
connected with the learning process in man and the lower ani- 
mals inform us, has the ability to substitute itself for re- 
sponses that produce it. So a task, dropped in the midst of 
the unpleasantness of great fatigue, will later call up not the 
activity attitude that would ensure its continuance, but a re- 
action of aversion: we *want never to think of it again.* 

The efficiency of a mental worker is thus directly connected 
with his sensitiveness to fatigue stimuli. Not merely is the too 
fatigable individual, whose activity attitudes relax before the 
problem has governed associative processes long enough to 
progress towards solution, a failure; but the worker who is 
insensitive to fatigue until its products have accumulated so 
that the reaction when it does occur is violently unpleasant, 
is in danger of still greater disaster from the point of view of 
efficiency. For the problem that is dropped under the influence 
of a slight degree of fatigue may be resumed, but the problem 
dropped under the influence of profound fatigue is likely to be 
abandoned permanently. 

When fatigue puts an end to the activity attitude too soon 
for the highest degree of efficiency in work, it may be because 
the fatigue processes are really intense, owing to some tem- 
porary or permanent physiological weakness on the worker's 
part, or it may be because he has the bad habit of paying too 
much attention to fatigue sensations. As it is disastrous for 
efficiency when a worker disregards fatigue influences until 
they have become very intense, so it is in a less degree unfor- 
tunate if hislimen for a special reaction to fatigue sensations is 
too low. There are some persons, and the present writer is one 
of them, who can never work without giving a disproportionate 
amount of attention to the fact that they are working. Hence, 
indeed, they avoid nervous breakdowns and do not tend to 
abandon unfinished tasks finally and forever, as do some of 
their too enthusiastic friends after uninterrupted long periods 
of work; but they waste a good deal of time by dropping their 
tasks after very short periods of work because their attention is 



168 MOVEMENT AND MENTAL IMAGERY 

directed to slight sensations of fatigue. I do not know whether 
any reader can verify this experience from his own introspection, 
but I have repeatedly noted that on a morning when I am 
generally fatigued after loss of sleep, I produce an unexpectedly 
large amount of work; and I am inclined to lay this to the fact 
that, starting out tired, I take my fatigue sensations for granted, 
as it were, and pay less attention to them than usuaL Thus I 
am enabled to avoid the many needless breaks in my work 
ordinarily caused by the fact that I am distracted by the sensa- 
tions caused by the activity attitude. 

It would seem highly probable that to differences in innate 
and acquired or habitual permanence of the activity attitude 
and the proper amount of fatigabihty and attention to fatigue 
sensations are due differences in * general ability.' There is 
more and more accumulated evidence in favor of the supposi- 
tion called by Spearman (47) the theory of two factors; namely, 
that individual excellences in various kinds of mental work are 
due partly to special ability and partly to general ability. There 
can surely be no single condition so important for all kinds of 
work where mental ability is involved as the proper degree of 
persistence of the activity attitude. 

Our theory is, then, that the persistence of the motor innerva- 
tions connected with a problem idea is connected with the 
persistence of the activity attitude, a static movement system 
which associates itself, under favoring physiological conditions, 
with the attitude of unrest stirred up by the partial inhibition 
of a motor innervation connected with an instinct. It is a well 
known fact that a problem idea's influence will continue to be 
exerted after the idea itself has dropped out of consciousness. 
When the task is, for instance, the adding of a column of fig- 
ures, the worker does not have constantly to remind himself 
to add. Several careful studies have been made of the stages 
in the disappearance of the directing idea from consciousness, 
under various conditions. A comparative examination of the 
results of these studies indicates that such stages are of three 
different types. There is, first, the case where the problem idea 



THE PROBLEM OR PURPOSE 169 

is fully conscious at the time when it exerts its effect: the ob- 
server says to himself, *I must add/ or, *I must think of an 
opposite,' whatever the case may be. In the second type of 
effectiveness of the problem idea, it appears somehow fused 
with the stimulus that is to be responded to, and the stimulus 
is apprehended in a particular way, or has certain features 
added to it, as the result of the problem idea's operation. Thus 
in Ach's (2) experiments where the task consisted of simple 
arithmetical operations, the numbers were visualized with a 
plus sign between them, or one over the other to facilitate the 
operation of subtraction. The third type of case differs from 
the second rather in degree than in principle: it occurs when, 
with more complicated problems, a certain means of solving 
them, a certain method which aids in the fulfilling of the task, is 
adopted : this method may be in consciousness while the prob- 
lem idea itself is not. Thus in Grunbaum's (46) experiments, 
where very complicated sets of figures were shown for a very 
brief interval and the observers had to detect similar figures 
in the groups, they devised various schemes to help themselves. 
The second and third types are only cases where some other 
innervation has substituted itself for the innervation which 
the problem idea originally involved, and this substitute motor 
process persists in the place of the original one. Thus instead 

of saying each time, *I must add,' the verbal formula, ' 

and are ,' remains in readiness, or the plus sign per- 
sists, or the more elaborate scheme which aids in solving a 
more complicated problem remains in a state of persistent 
readiness to be excited. Of course the processes underlying the 
memory after-image and perseveration, the readiness of move- 
ments to be repeated, are strong factors aiding in the solution 
of problems, but the peculiar feature that distinguishes either 
the original problem idea, or the surrogate that later comes to 
replace it, is association with the activity attitude. 

There are cases where apparently the whole physiological 
process underlying directed thought ceases to have a conscious 
accompaniment and yet proceeds effectively, as later conscious 



170 MOVEMENT AND MENTAL IMAGERY 

processes show. In many such cases the activity attitude per- 
sists : there are times when I am puzzHng over a difficulty, and 
remain for an appreciable interval conscious of the activity at- 
titude, of strained attention, but of little else in the way of 
imagery, verbal or otherwise; yet at the close of the interval 
I find my associative dispositions have combined in a new pat- 
tern. Sometimes the activity attitude itseK is absent: a new 
idea, the solution of a problem, flashes on one in the midst of 
idle revery on other subjects. Here it is evident, since there is 
no persistent attitude to help the persistence of the problem's 
influence, that it must be due entirely to perseveration. 

Clearly the more practised a set of movements is, the more 
it will tend spontaneously to repeat itself, or to perseverate. 
Thus it is along lines in connection with which we have done 
much thinking that unconscious * thinking ' goes on : we do not 
have sudden inspirations on subjects about which we have 
done little conscious meditation. So the simpler tasks, such as 
adding or rhyming or thinking of opposites, very quickly come 
to depend entirely on perseveration, because they are tasks 
already so familiar and so well practised. So, too, when a task 
is set that can be solved in a number of different ways, not 
only does delay occur because a variety of movements is set in 
readiness, but such a task has to depend longer on the activity 
attitude than does a task that can be solved by only one set of 
movements, for in the latter case the single set of movements 
through being repeated and practised gets much help from 
perseveration. The fact that a fully determined problem is 
performed with greater ease and speed than a vaguely deter- 
mined one is called by Ach (2) the *Law of Special Determi- 
nation,' and he derived it from experiments by the follow- 
ing methods. His observers were required to make one set 
of reactions with predetermination. These were as follows: 
simple reactions to white cards as stimuli; reactions where 
sometimes other stimuli were given to which no reaction was 
to be made; discrimination reactions, where two kinds of 
stimuli were intermingled and the observer was to react as soon 



THE PROBLEM OR PURPOSE 171 

as he recognized what a particular stimulus was; reactions 
where one kind of stimulus was to be responded to by a move- 
ment of the right hand and the other by a movement of the 
left hand; reactions where there were four different kinds of 
stimuli to be responded to by four different movements. An- 
other set of reactions was made without determination. These 
included two classes, those where the stimulus was indeter- 
minate and those where the response was indeterminate. In the 
first case, two stimuli were shown together, and the observer's 
instructions were to choose which one he would respond to, but 
always to make the same movement in response to the same 
kind of stimulus. Thus if a red card and a blue card were shown 
together, he might respond to either one, but if he chose to 
respond to the red card he must do so by a movement of his 
right hand. In the second case, cards with numbers were shown 
to the observer, who might perform any of several different 
arithmetical operations he chose with the numbers presented. 
The more complete and particular the instructions, the less 
liberty of choice left to the observer, the shorter was the reac- 
tion time. 

Just the same law is shown in experiments on so-called 
'forced associations.' When a word is given to an observer and 
he is told to answer with the first word that occurs to him, it 
regularly takes him a little longer to do so than if he is in- 
structed beforehand that he must respond with a particular 
kind of word, for instance a rhyme, or a word denoting the 
class to which the object named by the stimulus word belongs. 
This at least is the testimony most generally given by those who 
have compared *free association times' with * forced associa- 
tion times': thus Wells (150) says that controlled associations, 
if simple, are always shorter than free ones. Wreschner (159), 
on the other hand, says that a given type of association occurs 
more rapidly when it is free than when it is prescribed: that is, 
for example, an observer would respond to the word *dog' with 
the word * animal' more quickly if he just 'happened' to do so 
than if he had been previously instructed to think of a superior 



172 MOVEMENT AND MENTAL EMAGERY 

concept to dog. "Every Aufgahe" says Wreschner, "exerts 
a certain inhibiting influence, in consequence of which the idea 
corresponding to it comes to consciousness a Httle late/* 
Wreschner does not limit this statement to the complexer 
tasks, but it would certainly appear that he should do so. If 
a problem is simple, it certainly ought to be performed more 
quickly when the movements which it involves are set in 
readiness beforehand. E it is complex, one can see why the 
more complicated set of movements should involve delay as 
compared with a free reaction. The Law of Special Determina- 
tion holds without exception: if a forced association means that 
only a few movements have been set in readiness, and a free 
reaction means that a great many movements have been set 
in readiness, then the free association will take longer than the 
forced one. But as a matter of fact the reactions given under 
the instructions to say the first word that comes into one's 
head are often not free at all in the sense that many possibili- 
ties are previously excited: for in the first place, when the 
stimulus word is not known, the expectation is wholly vague, 
and in the second place the reaction word that is given is often 
based on an associative disposition of such strength through 
much repetition that no other possibility can claim the field. 
The person who is given the stimulus word * black' is likely 
to respond * white' with no interference of other associative dis- 
positions, because no other disposition is of anything like equal 
strength. The Law of Special Determination is clearly illus- 
trated in the fact that it regularly takes longer to pass from a 
more general idea to a less general one, as from * animal' to 
*dog,' than from a less general to a more general idea. * Animal ' 
may suggest many subordinate classes besides 'dog,' but 'ani- 
mal' is by far the most obvious superior concept to *dog.' 

The advantage of definite preparation and of the persevera- 
tive tendency that is involved in having a special and fully 
determined problem at the outset is further shown by the fact 
that when a person is given vague and indefinite instructions 
he very soon helps himself out by adopting a stereotyped 



THE PROBLEM OR PURPOSE 173 

method and sticking to it; that is, he adds self-imposed tasks 
to the one he has been set. In the very interesting experi- 
ments of Koffka (63), where the instructions were quite gen- 
eral, such as, "React, by making a signal, when the stimulus 
word has suggested an idea to you"; or, "React when it has 
suggested an idea and this idea has suggested another"; the 
observers imposed on themselves more special tasks, such as 
those of reacting as quickly as possible, or of reacting only with 
words, or of reacting always with synonyms, or of thinking of 
individual examples. Koflka therefore adds to Ach's conception 
of * determining tendencies,' or the influences which proceed 
from problem ideas, that of * latent attitudes' which have the 
effect of determining tendencies but do not proceed from prob- 
lem ideas. It seems to me that these seK-imposed problems can 
be explained simply in the following way. A very general prob- 
lem sets in readiness a number of methods for its solution. One 
of these methods happens to be the first one adopted, and sim- 
ply perse verates : since the influence of perseveration involves 
so much less fatigue than the influence of the activity attitude, 
it is not interfered with and becomes increasingly strong. 



CHAPTER IX 

THE FORMATION OF NEW MOVEMENT SYSTEMS UNDER 
THE INFLUENCE OF PROBLEMS 

In this chapter we shall attempt very briefly to sketch an 
account of the way in which movement systems become broken 
up and new ones constituted out of old ones under the influ- 
ence of purposes. That is, we shall consider the processes of 
thinking. And it is not primarily with the conscious accom- 
paniments of such breaking up of old systems and formation 
of new ones that we shall be concerned. These conscious accom- 
paniments will be discussed in the chapter that follows. It is 
rather with the mechanism of thinking than with the way it 
feels to think, that we have just now to deal. 

The logician says that an act of reasoning is a complex act of 
judgment, consisting in fact of three judgments, which he calls 
respectively the minor premise, the major premise, and the 
conclusion. Thus if I reason that the weather must be cold this 
morning because I see steam rising from the nostrils of horses, 
my process of thought may be resolved into the minor premise 
that steam is rising from the horses' nostrils, the major pre- 
mise that whenever steam thus rises the weather is cold, and 
the conclusion that the weather is cold to-day. It would cer- 
tainly appear that the process of judgment, by which we make 
the assertion that a thing is something else, that A is B, must 
be fundamental to processes of reasoning which can thus be 
reduced to series of judgments. 

What, then, is the essential nature of a process of judg- 
ment? We are, as has just been said, not concerned just now 
with the question as to the nature of the conscious processes 
that accompany judgment. Marbe ^ wrote a monograph whose 
conclusion is that there are no conscious processes which 
* Experimentell-psychologische Uniersuchungen uber das Urteil. Leipzig, 1901. 



FORMATION OF NEW MOVEMENT SYSTEMS 175 

especially characterize judgment. Our present point of at- 
tack is this : how are movement systems related and constituted 
when, instead of applying the verbal formula * A suggests B,' 
we use the formula, *A is B'? 

TVTien A suggests B, either the two movement systems, A 
and By form part of one and the same system, so that there 
exist associative dispositions between them as wholes, or some 
movement or smaller movement system contained in A is 
identical with a movement or smaller movement system con- 
tained in B. In the language of the older psychology, either 
A and B are linked by contiguity, as having been once experi- 
enced together, or they are linked by similarity, as having a part 
in common. The sight of one person may suggest another with 
whom he is frequently met, or it may suggest some one whom 
he has never seen but who has a Hkeness to him. We get the 
typical cases of *A suggests B' in unguided revery, and it may 
be noted that when A has suggested B its influence generally 
stops. Gazing at a chandelier in a hotel lobby, I find myself 
thinking of Galileo; the chandelier has ceased to concern me 
and my attention has flown to ideas connected with the be- 
ginnings of modern science. 

Now, one difference between *A suggests 5' and 'AisB^is 
that in the latter case A does not drop out of the account. It 
really was the slow swinging of the chandelier to and fro that 
suggested Galileo watching the cathedral lamp. The move- 
ment systems succeeded each other in approximately the fol- 
lowing order: (1) systems concerned with the chandelier as a 
whole; (2) systems concerned with its slow movement to and 
fro; (3) systems concerned with Galileo and linked, as the 
chandeUer was, with the *slow swinging' systems. Now, did I, 
in the process of making this connection, say to myself, *That 
chandeHer is swinging'? Or did I pass at once on to Galileo 
without pausing to notice the connecting link? If I said, *The 
chandelier is swinging,' I made a judgment: if not, the case 
was one of mere * association of ideas.' The peculiar feature of 
making the judgment about the chandeHer would be that the 



176 MOVEMENT AND MENTAL IMAGERY 

movement systems concerned with the chandelier as a whole would 
recur for an instant. The sequence of movement systems would 
in this case be: (1) systems concerned with the chandeHer as a 
whole; (2) systems concerned with its slow movement to and 
fro; (3) a recurrence of the systems concerned with the chande- 
lier as a whole ('the chandelier is swinging,' not merely * swing- 
ing' as a phenomenon ready to detach itself from this particular 
context). In a judgment, a part of the movement system con- 
cerned with the subject lasts over after the rest has ceased to 
act (the swinging of the chandelier is attended to after the rest 
of it has dropped from attention). This smaller system, a com- 
ponent part of the subject system, is the predicate system. Its 
emergence and persistence is followed by a recurrence of the 
subject system as a whole. Thus, the sequence is *A — B — B- 
as-a-part-of-^.' And the subsequent associative dispositions 
will be determined not only by the predicate B, but by the 
predicate in connection with the subject ^. If in the train of 
revery in which I passed from the chandeHer to Galileo, I had 
really stopped to make the judgment * The chandelier is swing- 
ing,' my thoughts for the next instant or so would have dwelt 
with the phenomenon of the swinging chandelier, and not 
merely with swinging objects in general. I might, for instance, 
have wondered if it were securely hung. 

Note that I spoke just now of * stopping ' to make a judgment. 
It always involves delay to make a judgment, because it al- 
ways involves going back on one's tracks, as it were, to revive 
the movement systems connected with the subject of the judg- 
ment after one has passed on to the predicate systems. For this 
reason, judgments are most commonly made under the influ- 
ence of a problem which secures the persistent influence of the 
subject system. Thus for example if I were a builder or an 
electrician, with a permanent problem of investigating chande- 
liers and such objects, I should be much more likely, after 
noting the swinging, to recur to the chandelier instead of going 
on to Galileo. The judgments we make in the course of a day 
are usually determined by our problems: if one is a painter, on 



FORMATION OF NEW MOVEMENT SYSTEMS 177 

going into a room one makes judgments about the pictures on 
the walls; if one is an electrician, one makes judgments about 
its lighting arrangements. Thus Watt (148) could say that 
determination by an Aufgabe, sl problem idea, is the character- 
istic feature of a judgment. 

Now, a process of reasoning or inference is a judgment made 
indirectly. When for any reason I cannot put my head outside 
the window and feel for myself that the weather is cold, I have 
to arrive at the conclusion by inferring it from some such fact 
as that the horses are steaming. It is self-evident that if a 
simple judgment means delay, a process of reasoning means a 
longer delay; and it would be almost impossible for so long 
a delay to occur without the influence of a problem idea, and, 
in more complicated processes of reasoning, the activity 
attitude. 

In reasoning, as in judgment, we start of course with the 
subject we are reasoning about. And always in reasoning, as 
often in judgment, we start also with the thing we want to 
prove about our subject; the predicate of our conclusion. I 
have an interest in knowing whether the weather is cold before 
I begin to reason about it: if "cold" had not entered my mind 
there would be no reasoning about it. Professor James, calling 
the predicate of the conclusion P, says, "Psychologically, as 
a rule, P overshadows the process from the start. We are 
seeking P, or something like P " (57, Volume II, page 338). This 
means, of course, that P, the predicate of the conclusion — 
coldness, in the example we have been using — acts together 
with the subject as a problem idea. We have, then, in opera- 
tion two systems of tentative movements, those connected with 
the subject (the weather to-day), and those connected with the 
predicate (cold). The outcome of reasoning is the setting into 
action of movement systems that are connected with both of 
these systems; any other movement systems will be inhibited 
by the persistent recurrence of these two as the problem idea. 
We want to continue our thinking and planning on the basis of 
the ascertained fact that it is or is not a cold day. 



178^ MOVEMENT AND MENTAL IMAGERY 

Now, surely, it may be supposed, if we have both the subject 
and predicate systems excited, if we are attending to the 
weather and the possibiHty of its being cold, these two sys- 
tems must have old associative connections so that the proc- 
esses of association can go on without any reasoning being 
necessary. We have experienced cold days before, and we know 
what can and what cannot be done on them. This is what is 
called proceeding on an hypothesis. But the difficulty is that 
these old associative dispositions do not really connect * to-day *s 
weather ' with the predicate • cold ' ; they only connect ' weather ' 
with *cold': If the movement systems connected with our 
true subject, * to-day's weather,' remain active as apart of the 
problem, the mere hypothesis that it is cold will be soon in- 
hibited by a return to the full problem. Not until some member 
of the full movement system which constitutes * to-day's 
weather,' a very complicated system involving much more than 
'weather' in general, proves to have associative dispositions in 
common with * cold,' will the delay and constant reference back 
to the problem cease. Until that time, while we may be saying 
to ourselves, "If it is cold, I'd better take a closed cab, and 
have more coal put on the furnace before I go,*' these medita- 
tions will constantly be interrupted by the recurring question, 
"But is it really cold?" 

But what about fallacies, mistakes in reasoning? We can- 
not fully describe the process of correct reasoning without ex- 
amining the ways in which it may go wrong. Reasoning or 
inference proceeds by the discovery of what the logicians call 
the middle term (the steaming breath of the horses, in our 
example), which has associative dispositions linking it with 
both the movement systems of the problem, the subject sys- 
tem and the predicate system. Now, does the correctness of the 
reasoning depend on the strength of these associative disposi- 
tions? Does it, in our example, for instance, depend on the 
number of cold days on which we have seen the horses' breath 
rising like steam in the air? 

Not so much on the strength of these dispositions, it may 



FORMATION OF NEW MOVEIVIENT SYSTEMS 179 

be said in answer, as on the absence of any dispositions connect- 
ing the terms of the inference with incompatible movements. 
It does not so much matter how often we have noticed steam- 
ing horses on cold days, provided that we have never seen this 
condensation of breath vapor on a warm day. If we have, it 
cannot be used as a trustworthy middle term. For the move- 
ment system corresponding to the subject about which we 
are reasoning and that corresponding to the predicate, in order 
to combine to determine future systems, have to form them- 
selves into a simultaneous system. And a simultaneous system 
cannot contain incompatible movements. They may per- 
fectly well enter into successive systems, but not into simul- 
taneous ones. Therefore the existence in any effective strength 
of a single associative disposition representing a * negative in- 
stance * will injure the functioning of the whole system. 

Yet people do ignore negative instances, and do guide their 
conduct by highly fallacious reasoning? Yes; by a loss of the 
original and true problem idea. They forget that their reason- 
ing is about this particular case, and not about some other case 
which more or less resembles it. The subject or the predicate 
of their reasoning, by the many ways in which older disposi- 
tions and systems can modify and corrupt newer ones, gets 
altered; as my memory image of the painting adapted itself 
to older associative dispositions. Old prejudices and even mere 
verbal associations exert their contaminating effect. This is 
especially apt to be the case if the first attempt at reasoning 
out the situation fails: the activity attitude is fatigued, and 
the easier path is taken of reasoning about something more or 
less like the true subject of the problem, or accepting a some- 
what different predicate which is less incompatible with the 
subject. 

That fallacies do arise by such modifications and contamina- 
tions of the subject and predicate movement systems which 
should act jointly as the directing or problem idea, or more ac- 
curately, as its motor basis, may be illustrated by taking ex- 
amples of the typical and classical fallacies which the logicians 



180 MOVEMENT AND MENTAL IMAGERY 

term respectively the fallacy of the undistributed middle term, 
of illicit process of the minor term, and of iUicit process of the 
major term. Suppose a naturalist should argue that a new 
specimen brought in for him to examine was a bird because it 
had wings. His argument would be formulated by the logician 
as follows: "Birds have wings; this creature has wings, there- 
fore this creature is a bird "; and the logicians would say that 
the naturalist had committed a fallacy known as that of 'un- 
distributed middle term,' in that only part of the middle term, 
* creature having wings,' is referred to in each premise. Now the 
psychological process underlying this fallacy is something like 
the following. The naturalist starts with attention to the speci- 
men before him and to the idea of several different classifica- 
tions for it, *bird' among the rest. Attention to these objects 
involves the activity of certain movement systems; and the 
system corresponding to *bird' combines with the system cor- 
responding to *this specimen,' to strengthen the movements 
corresponding to * wings,' which form a part of the total system 
for *this specimen.' But the movements corresponding to 
'wings' belong also in other systems which contain elements 
incompatible with the *bird ' system; insects have wings. The 
fallacy is committed because the *wing' system is not allowed 
to develop far enough to excite these incompatible movements. 
In other words, the middle term is not really * wings,' but *bird 
wings'; since the reasoner started with birds in his mind, it is 
easier and involves less delay to think of bird wings than to 
think of wings in general, which would recall to him the other 
winged creatures that are not birds, and prevent him from 
committing the fallacy. Here it is the strong influence of the 
predicate, birds, the haste, as it were, to reach a conclusion as 
soon as possible, that contaminates and limits the middle term 
system. 

As an example of illicit process of the minor term, take the 
case of a person who argues from one specimen of a class that 
all members of the class are like it. A person meets an ill- 
informed college student, and proceeds to write a letter to the 



FOKMATION OF NEW MOVEMENT SYSTEMS 181 

newspaper about the failure of college education. His reason- 
ing formulates itseK thus: This person is ill-informed; he is a 
college student, therefore all college students are ill-informed. 
Here the trouble evidently is that the middle term, *this per- 
son,' has contaminated and practically substituted itself for the 
minor term, * college students,' the true subject of the reason- 
ing. The reasoner has not allowed the system corresponding to 
'college students' really to develop itself; if it had, surely nega- 
tive instances would have been suggested. But a little more 
time and patience would have been needed for the full develop- 
ment of the * college student' system, and the system *this per- 
son as a college student ' is already on the field; so it is allowed 
to assume the functions of a minor term when its true function 
is that of a middle term. 

Illicit process of the major term is committed when the predi- 
cate of the conclusion is contaminated and altered. Suppose 
that one is occupied with the question as to whether a particu- 
lar piece of property is or is not exempt from taxation. The 
idea of its being exempt suggests the idea of church property, 
which is exempt; but this property is not church property. It 
is therefore rashly and fallaciously considered to be not exempt. 
The trouble here is that the system underlying * exempt from 
taxation' is not allowed to develop fully; instead of becoming 
the * exempt from taxation' system, it is really the system cor- 
responding to * church property exempt from taxation.' If it 
developed as it should, there would be suggested other kinds of 
property, such as public school property, that are exempt and 
that contain no features at all incompatible with the property 
about which one is reasoning. 

In all three of these fallacies which the logicians call formal 
fallacies, one of the terms contaminates and alters another, 
which is not allowed to develop fully. In the 'undistributed 
middle' example, the major term contaminates and limits the 
middle term; in the 'illicit minor' case the middle term limits 
the minor term, and in the case of 'illicit major' the middle 
term limits the major term. In the so-called * material fallacies/ 



182 MOVEMENT AND MENTAL IMAGERY 

as contrasted with these * formal fallacies,' the contamination 
of the systems underlying the terms has its source in the in- 
fluence of systems outside the argument; in the thinker's general 
habits and prejudices. Take as a single illustration an example 
given by Creighton of the so-called fallacy of ambiguous middle 
term: "Partisans are not to be trusted; Democrats are parti- 
sans; therefore Democrats are not to be trusted." "The middle 
term, * partisan,'" says Creighton, "is evidently used in two 
senses in this argument. In the first premise it signifies per- 
sons who are deeply or personally interested in some measure; 
and in the latter it simply denotes the members of a political 
party" (25, page 160). This transformation of a term into a 
different term does not show the influence of any of the other 
terms in the argument: the influences which bring it about may 
be almost infinitely varied, and may include, as was said above, 
the thinker's habits of mind and also the influence of the situa- 
tion as a whole, or of some suggestion from his antagonist in 
argument. As Creighton points out, the fallacy would not be 
very hkely to occur in so simple an example as the one just 
given, but might easily be produced in the course of a long train 
of reasoning. 

Fallacies, whatever their immediate cause, always have as 
one of their causes laziness. Correct reasoning, involving the 
full development of movement systems, requires more delay 
than incorrect reasoning, which involves a restricted and im- 
perfect development: delay means that the activity attitude 
must be longer continued, and the activity attitude is fatiguing. 
When it relaxes, associative dispositions take the easiest way. 

The whole process of creative thinking may be conceived in 
some such fashion as the following. The thinker has first in 
mind the idea of his problem or purpose. This usually involves 
at least two great movement systems, which are as yet discon- 
nected. Tarde^ says that invention always results from the 
interaction of two needs : two beliefs, two desires, or a belief and 
a desire. The essential necessity for the creative thinker is that 
^ La logique socide. Paris. 1898. 



FORMATION OF NEW MOVEMENT SYSTEMS 183 

he shall hold in activity both these systems in their full com- 
plexity, never allowing either one to become contaminated by 
the other or by his mental habits and prejudices. In each of the 
systems every component part must be allowed in its turn to 
become predominant: that is, both parts of the problem must 
be fully analyzed. The failures in creative thinking, whether it 
be the formation of a scientific hypothesis, the construction of 
a machine, or the production of a work of art, always come from 
suffering a part of the problem to be neglected or falsified: some 
essential condition is overlooked. As the various component 
parts of the two problem systems come into especial activity, 
they find various common motor outlets, the tentative hypothe- 
ses or suggestions towards the solution of the problem. But 
each of these must be inhibited while the other parts of the 
problem systems are allowed to come into activity, until a direc- 
tion of motor discharge is found which is common to them all, 
and a solution is reached which leaves no part of the problem 
out of account. Constant reference back to the problem ideas 
in their uncontaminated purity; the acceptance of no partial 
solution, no working out of a problem which is a little changed 
from the original one; this is demanded of successful creative 
thinking, and it is possible only through the persistent domi- 
nance of the problem ideas, with the aid of a persistent and 
recurrent activity attitude. 

The difference between creative imagination and creative 
thought is described by Meumann (82, page 14) as consisting 
in the fact that for imagination, imagery is an end in itself, 
while for thought imagery is only a means to an end. This 
statement should be modified, I think; the only form of imag- 
ination where the image can be called even relatively an end in 
itself is aesthetic imagination, and even here it is not really the 
creation of the imagery that is the end. Can an image ever be 
an end in itself; can anything, in an organism formed for the 
purpose of reacting adequately upon its environment, be an 
end except a movement? The scientific theorist's aim is to 
construct a system of tentative movements that will lead to a 



184 MOVEMENT AND MENTAL IMAGERY 

series of successful full movements in response to the world 
outside: the inventor's aim is to construct in thought a machine 
that will work upon the outer world. The creator in the field 
of aesthetics is indeed contented that his work shall have no 
effect in the larger movements which influence the external 
world : he is satisfied that his product shall continue to influence 
only the realm of imagery and the tentative movements upon 
which imagery is based. But we must remember that the aes- 
thetic creator seeks to produce not only imagery but the affec- 
tive reaction to imagery : not merely tentative movements, but 
the full motor response of those pathways which lead to the 
movements involved in emotion. The true statement, then, of 
the distinction which separates, not imagination from thought, 
but aesthetic imagination and thought from other forms of 
imagination and thought, is that the problem of the creative 
thinker in other than aesthetic fields involves the production of 
movements which affect the external world; the problem of the 
aesthetic creator involves the production of movements which 
remain as it were concealed within the other human organisms 
who contemplate his work: the tentative movements on which 
their mental imagery rests, and the full but self -limited move- 
ments which constitute their emotional responses. 



CHAPTER X 

IMAGELESS PROCESSES 

"If," said the philosopher Hume, "you cannot point out 
any such impression, you may be certain you are mistaken, 
when you imagine you have any such idea*' (54, page 65). 
For a long time this principle virtually ruled psychology, and 
an idea that was vague and obscure, and could not trace its 
origin directly to sensations, was dismissed as no proper object 
of scientific study. It was James who, in a chapter familiar to 
every student of psychology, declared his wish for a "reinstate- 
ment of the vague to its proper place in our mental life " (57, 
Volume I, page 254). For it is evident to any one who carefully 
observes his own conscious experience that much of our think- 
ing and feeling cannot be adequately described as made up of 
the colors and brightnesses which the eye supplies, the many 
tones and noises that the ear gives, the four taste qualities, the 
possibly nine smell qualities, the four qualities from the skin. 
The inner life of the mind, all that varied and eventful complex 
of processes which may occur when, lying in a silent and dark- 
ened room, we review the experiences of a day and decide on a 
course of action for the morrow, is not recognizably describable 
as a kaleidoscopic pattern of colors, tones, smells, tastes, and 
skin sensations, centrally excited. James has enumerated for 
us some of the parts of our conscious experience which espe- 
cially, he thinks, refuse to be identified with sensations from the 
old five senses. He divides them into * transitive states,' or 
relational feelings, and * feelings of tendency.* In discussing 
* transitive states' he says: "There is not a conjunction or a 
preposition, and hardly an adverbial phrase, syntactic form, or 
inflection of voice, in human speech, that does not express some 
shading or other of relation which we at some moment actually 
feel to exist between the larger objects of our thought." "We 



186 MOVEMENT AND MENTAL BIAGEEY 

ought to say a feeling of and, a feeling of rf, a feeling of hut, and 
a feeling of hy, quite as readily as we say a feeling of blue or a 
feeling of cold." Under the head of * feelings of tendency/ he 
enumerates such experiences as the feelings occasioned by the 
words *wait,' *hark,' *look'; the vague consciousness that rep- 
resents a forgotten name, a consciousness sufficiently positive 
to reject a wrong substitute; the experience of recognizing a 
thing as familiar without being able to * place' it; the feelings 
corresponding to * naught but/ * either one or the other,' 'al- 
though it is, nevertheless,' *it is an excluded middle, there is 
no tertium quid,^ *who?' *when?' *where?' *no,' *never,' *not 
yet'; "that first instantaneous glimpse of another person's 
meaning which we have when in vulgar phrase we say we * twig ' 
it"; "one's intention of saying a thing before he has said it"; 
"that shadowy scheme of the * form' of an opera, play, or book, 
which remains in our mind and on which we pass judgment 
when the actual thing is done"; "the awareness that our def- 
inite thought has come to a stop" and the 'entirely different' 
" awareness that our thought is definitively completed " ; finally, 
the awareness "that we are using such a word as man in a gen- 
eral and not an individual sense." This list was no doubt in- 
tended by James to be merely illustrative and not exhaustive. 
Every one will recognize these experiences as being highly im- 
portant, and as not obviously, at least, analyzable into colors, 
sounds, tastes, smells, and skin sensations. 

Many psychologists, some following James's lead, others 
independently, have contended for the existence of non-sensa- 
tional or imageless conscious processes. 

Stout (133), for example, says: "Professor James dwells 
only on the part played by psychic fringes in higher cognitive 
states. He fails to bring out its importance for sense perception 
also. But a little consideration shows that complex sensible 
objects do not appear to the percipient in all their sensible de- 
tail. When I look at a house, what is actually seen together 
with what is mentally pictured constitutes only a small part of 
the object as it is perceived. ... An imageless representation 



IMAGELESS PROCESSES 187 

of the whole is conjoined with the sensible appearance. ... At 
the most, only the last two or three notes of a melody are per- 
ceived at its close, and yet the musically gifted are aware of it 
as a whole. . . . All perception of a series of changes as forming 
a whole involves imageless apprehension." The imageless 
processes in which Stout is most interested are the feelings of 
tendency in thinking, involving "not only consciousness of 
whither our thought is going, but backward reference to what 
it has already achieved." 

Spencer (131) divided conscious processes into two classes, 
which he called 'feelings' and * relations between feelings.' By 
feelings he meant sensations, peripherally or centrally excited. 
James's feelings of ' if ' and * but ' would evidently be classed by 
Spencer as relations between feelings. The differences between 
feehngs and relations between feelings, according to Spencer, 
are, first, that the latter have no duration, "occupy no appre- 
ciable part of consciousness"; they are "momentary feelings 
accompanying the transition from one conspicuous feeling to 
another"; and secondly, that as a result of their fleeting char- 
acter they are unanalyzable: "whereas a relational feeling is 
a portion of consciousness inseparable into parts, a feeling 
ordinarily so-called is a portion of consciousness that admits 
imaginary division into like parts which are related to one 
another in sequence or co-existence." 

In 1901 Calkins (20), accepting the doctrine of James and 
adopting the term 'relational element' from Spencer's 're- 
lational feeling,' gave as an enumeration, admittedly incom- 
plete, of such non-sensational components in our experience, 
the following list: feelings of one and many, of 'and' and 'but' 
(connection and opposition), of like and different, of more and 
less, of generality, or that which, added to a percept or image, 
makes it a general notion; of clearness (which feeling constitutes 
the process of attention: an attended-to percept is the percept 
plus the feeling of clearness); a feeling of the combination of 
elements in a percept; the feeling of familiarity (which is really 
a fusion of two relational elements, namely, the feelings of 



188 MOVEMENT AND MENTAL IMAGERY 

sameness and pastness) ; and the feeling of wholeness (which is 
a distinguishing feature of the process of judgment) . Most of 
these feelings are not further described, and Calkins, like James, 
emphasizes the great diflSculty of observing them introspec- 
tively: the feeling of pastness, however, is depicted as "the 
consciousness of an irrevocable fact, linked in two directions 
with other facts." 

Woodworth (157) in 1906, as a result of experiments where 
the observers were asked to go through certain simple thought 
processes, reached this conclusion: "In addition to sensorial 
elements, thought contains elements which are wholly irredu- 
cible to sensory terms. Each such element is sui generis, being 
nothing else than the particular feeling of the thought in ques- 
tion. . . . There is a specific and unanalyzable conscious quale 
for every individual and general notion, for every judgment and 
supposition. An image may call up a meaning, and a meaning 
may equally well call up an image. The two classes of mental 
contents differ in quality as red differs from cold, or anger from 
middle C." Non-sensational processes were discovered in 
another direction by Mach (74) in 1886, when he posited, co- 
ordinate with colors, tones, and the other ordinary sense quali- 
ties, space and time sensations. A visual object like a house, he 
maintained, gives us, besides color sensations, space sensations 
of a certain size and form. The perception of a melody in- 
volves, over and above the tone sensations, a sensation of its 
temporal form. This general position was later greatly de- 
veloped by Ehrenfels (31), Meinong (78), Cornelius (24), and 
Witasek (152) : the opinion which they all have in common is 
that when sensations occur in a group, a new conscious ele- 
ment is produced which represents the togetherness of the 
elements, the form and character of their combination. Thus, 
a melody played in different keys has all its tonal elements 
quite different, but the form quality is identical and is recog- 
nized as such. 

Still another development of the notion of conscious proc- 
esses which are not reducible to sensations as elements was 



IMAGELESS PROCESSES 189 

suggested by Mayer and Orth (76) in 1901. They made an 
introspective study of the processes that intervene between the 
giving of a stimulus word to an observer and the pronouncing 
by the latter of some word suggested to him by the stimulus 
word. These processes they classified as ideas (made up of 
centrally excited sensations), will processes, and what they 
termed, at the suggestion of Professor Marbe, * Bewusstseins- 
lageriy * consciousness attitudes,' or, more briefly translated, 
'conscious attitudes.' They defined these merely negatively, 
as being neither ideas nor volitional processes. In his later 
work, "Gefuhl und Bewusstseinslage," Orth (102) says of the 
conscious attitudes that they are unanalyzable. They fall, he 
holds, into two groups : first, those of which introspection can 
only declare the existence without characterizing them further, 
and second, those whose significance for the psychic process can 
in some degree be determined. As an example of the first, the 
indescribable class, he cites the following introspection. The 
observer (no less skilled an introspector than Professor Kiilpe) 
was given the task of subtracting 217 from 1000. He reported: 
"Distinct visual images of 1000 and 217, the latter written 
under the former. They elicited the spoken word ' seven hun- 
dred,' and after a little pause the words * eighty-three.' The 
pause was filled with a peculiar conscious attitude, not further 
to be described." To the second class belong such states as 
doubt, certainty, uncertainty, contrast, agreement. Conscious 
attitudes are "something quite peculiar, which I find in my 
consciousness, without being able to call them feeling, sensa- 
tion, or idea, because they are entirely unlike these psychic 
processes." They are obscure, ungraspable. They have more 
to do with knowledge than with feeling. To the suggestion that 
they are only ideas in an obscure state, Orth replies that even 
so, since they are unique for introspection and since an idea as 
such cannot be obscure, they have a right to a special name. 
He would include under conscious attitudes the feeling of 
familiarity or knownness; he describes doubt as a conscious 
attitude accompanied by organic and kinsesthetic sensations. 



190 MOVEMENT AND MENTAL IMAGERY 

and mentions also conscious attitudes of remembering, know- 
ing, effort, belief, uncertainty. Some of these remind us 
strikingly of those "ideas of reflection" which Locke posited, 
in addition to sensations, as fundamental materials of our ex- 
perience: "by reflection," he said, he meant, "that notice which 
the mind takes of its own operations." ^ 

Messer (80) in 1906 gives a very long list of conscious atti- 
tudes. He suggests that they are of two kinds. The first kind 
includes those which are connected with words and represent 
the meaning of the words. He gives as illustrations the atti- 
tudes of understanding, ambiguity, and synonymity: one would 
say that these represent rather the relation of a word to its 
meaning than the meaning itself. Messer's second class com- 
prises the attitudes which occur when words are lacking, but 
one knows what one is going to say: here one may go to logic 
for the kinds of attitude concerned. Some examples are atti- 
tudes of reality, spatial properties, temporal properties, causal 
connection, relations such as identity, difference, similarity, 

* belonging together,' * lacking connection,' coordination, sub- 
ordination, supraordination, *more general,' *more concrete,' 
whole and part. These all represent relations between the 
objects of thought. There are also attitudes which represent 
the relations between the object of thought and the subject, 
that is, the thinker: such are the attitudes of knownness, 
strangeness, and positive or negative value. Again, there are 
attitudes which represent the relation of one's ideas to the prob- 
lem one is thinking on; such as the attitudes of * suitable' or 

* not-suitable,' * meaningful ' or * meaningless,' * correct,' * wrong,' 

* inadequate.' Finally, there are attitudes representing states 
connected with the process of problem solution itself: seeking, 
questioning, deliberation, doubt, certainty, uncertainty, dif- 
ficulty, ease, compulsion, * ought' and 'ought not,' readiness, 
possibility and impossibility, success and failure, fullness and 
emptiness of ideas, puzzle and confusion. As a cross-principle 

^ Essay on the Human Understanding (1689). Frazer's edition, Volume I 
p. 124. 



IMAGELESS PROCESSES 191 

running through all the classes of conscious attitudes, Messer 
suggests that they may be divided into the more intellectual 
and the more emotional or affective. 

Another type of imageless or non-sensational process was 
postulated by Ach (2) as a result of experiments on reaction 
time. The observers were shown white or colored cards, and 
received varying instructions: they were to press an electric 
key sometimes as soon as they had apprehended the character 
of the stimulus, sometimes as soon as they were aware of any 
stimulus at all: sometimes they were shown cards with two 
letters on them and told to choose either one as their stimulus, 
reacting to one with one finger and to the other, if they chose it, 
with the thumb. The observers reported the occurrence, in the 
interval between the instructions and the stimulus, of cer- 
tain imageless processes to which Ach gave the name * aware- 
nesses.' They were, he says, complex experiences, in which no 
* anschaulich ' elements, such as visual, auditory, or kinsesthetic 
sensations, or memory images of such sensations, could be 
demonstrated as determining the quality of the experience 
(2, page 210). 

Awarenesses, Ach maintains, are a "function of the excitation 
of reproductive tendencies." He groups them into four classes: 
awarenesses of meaning, that is, the awareness of the meaning 
of a word without its being present in the form of images; 
awarenesses of relation, whether an idea is the right one, that 
is, is in harmony with what we meant to think; awarenesses of 
determination, the awareness that an act is in harmony with 
what we meant to do; and awarenesses of tendency, the aware- 
ness that there is something more to be done. It would appear 
that awarenesses of meaning and tendency are, so to speak, 
forward-looking awarenesses, concerned in the one case with 
what we are going to think and in the other case with what we 
are going to do; while awarenesses of relation and determination 
are backward-looking awarenesses, concerned in the one case 
with what we originally resolved to think and in the other case 
with what we originally resolved to do. 



192 MOVEMENT AND MENTAL IMAGERY 

Perhaps the most difficult and obscure discussion of image- 
less processes is that of Biihler (18). With the aid of two ex- 
perts in introspection, Ktilpe and Durr, as observers, Buhler 
carried out at the University of Wurzburg some experiments 
on the nature of the process of thinking. In the first set of ex- 
periments, the observers were given questions to answer, such 
as, "Did the Middle Ages know the Pythagorean doctrine?" 
or aphorisms to understand: they then recalled and described 
all the processes which passed through consciousness in the 
interval between question and answer. In a later set of experi- 
ments the process of recalhng thoughts was studied: the ob- 
servers were given two related ideas and asked to establish in 
their own minds the connection: subsequently one idea was 
presented and the observers had to recall the other and to 
describe the process of recall. Or a sentence was given which 
required completion by another clause, which the observer had 
mentally to supply; later the completing clause was furnished 
and the original sentence called for; or two complete thoughts 
were presented, the observer having to find an analogy between 
them, and later, on the basis of this analogy, to supply one when 
the other was presented; or, finally, a series of thoughts was 
given in short sentences, and subsequently catchwords from 
the sentences were supphed, to recall the entire thoughts. On 
the basis of the introspective results, Buhler concludes that 
thought involves, first, ideas made up of sensations; secondly, 
feelings and conscious attitudes; and thirdly, thoughts. These 
last are simple, unanalyzable conscious processes, having no 
sense quality or intensity, but possessing clearness and vivid- 
ness. Of these thought elements there are three types : first, " the 
consciousness of a rule," of a method of solving problems; sec- 
ond, consciousness of relation, either of the parts of a thought 
(intra-thought relations), or of whole thoughts to each other 
(inter-thought relations) ; thirdly, consciousness of meanings. 

It is a discouraging field to survey, this of the non-sensational 
conscious processes. At least, one can hardly doubt, with such 



IMAGELESS PROCESSES 193 

an array of authorities before one, that events do happen in our 
mental Hfe which cannot be directly traced to any of the ex- 
ternal senses; which are not made up of remembered sights, 
sounds, smells, touches, or tastes. The psychologists who still 
believe, however, that sensation qualities are the only raw ma- 
terial of our experience, have usually had recourse to one or 
both of two ways out of their difficulty. Some of the so-called 
imageless processes, they argue, are just ordinary ideas, that is, 
images, in a state of indistinctness or vagueness. Thus the con- 
scious attitude of familiarity may be merely a vague, indistinct 
recall of the circumstances under which we last met the object 
recognized: awareness of the meaning of a word like *city ' may 
be a vague, unanalyzable jumble of the images which the word 
is capable of suggesting. So MuUer (89) urges that some of 
Orth's conscious attitudes are nothing but indistinct ideas; 
as when he speaks of a conscious attitude representing "the 
memory of a similarly smeUing substance used for toothache.'* 
Orth himself, as we have seen, does not deny that his conscious 
attitudes may be only ideas in a state of vagueness, but holds 
that they ought to have a name of their own. Further, Miiller 
says of Ach*s awarenesses that they are nothing but indistinct 
ideas. For instance, Ach calls the feehng that a name is just 
on the tip of our tongue, an awareness of tendency: it is 
simply, Mtiller argues, a very indistinct kinsesthetic image of 
the name. Or take the awareness that our task is not yet com- 
pleted, that we have something yet to do, we know not what: 
here also there is simply an indistinct idea. Unless, Mtiller 
maintains, the presence of indistinct ideas can be excluded, it is 
unscientific to bring in anything new and mysterious like an 
awareness: it is also much too easy. Biihler himself considered 
and rejected the notion that his thought elements are indis- 
tinct ideas, under two aspects : one of these he calls the conden- 
sation theory, according to which thoughts are condensed, ab- 
breviated series of images. This is untrue, he thinks, for surely 
such a condensation would not make the ideas lose all the char- 
acters of ideas, such as recognizable sensation qualities. (Pre- 



194 MOVEMENT AND MENTAL IMAGERY 

cisely such an effect, as we shall see, might be expected in an 
abbreviated and condensed series of images.) The other form of 
the * indistinct idea' theory Biihler rejects under the name of 
the * possibility theory ': thoughts are not subconscious images, 
for thoughts are perfectly clear and distinct. Evidently when 
Biihler says that imageless thoughts are distinct and Mtiller 
says that all imageless processes are indistinct images, they 
must each mean a different thing by * distinct.' 

Another promising opening for a sensational explanation of 
these imageless processes which so many psychologists dis- 
cover, is to say that they are made up of Jcincesthetic and organic 
sensations, either peripherally or centrally excited. An obvi- 
ous, though fortunately not the only or the best, reason for 
choosing these modalities of sensation as the material for (ap- 
parently) non-sensational processes is that we are so little in 
the habit of attending to them and analyzing their combina- 
tions that they may really be the components of almost any 
experience not evidently derived from other sources. Titch- 
ener (137) is strongly inclined to the opinion that " the 
imageless thoughts, the awarenesses, the Bewusstseinslagen 
of meaning and the rest" are "attitudinal feels," describable 
"in the rough" without difficulty as visceral pressures, dis- 
tributions of tonicity in the muscles of back and legs, difference 
in the sensed play of facial expression, and other kinsesthetic 
and organic sensations; and that "under experimental condi- 
tions, description would be possible in detail." Feelings of 
relation he is sure are in his own mind kinsesthetic, and more- 
over roughly localizable and analyzable. 

There are still other ways of disposing of alleged non-sensa- 
tional processes besides those of identifying them as obscure 
sensory images or as kinsesthetic and organic sensations. Mtin- 
sterberg (95) classifies some of these processes as properties of 
sensations; that is, he includes the spatial and temporal orders 
of sensations under the head of *form qualities' of sensation, 
while some, at least, of the conscious attitudes and relational 
elements fall in the class of * value properties' of sensation: 



IMAGELESS PROCESSES 195 

thus, tlie difference between the idea of a past event and the 
idea of an expected event is a difference in * value quahty.' 
Wundt (160) has a convenient scheme for deahng with all non- 
sensational processes: he recognizes besides sensational ele- 
ments simple feelings of many qualities, capable of entering 
into a great variety of combinations. This body of elementary 
feelings may be grouped into three classes, feelings of pleasant- 
ness or unpleasantness, feelings of strain and relaxation, and 
feelings of excitement or depression. It is an easy matter to ex- 
plain any mysterious imageless process as due to the presence 
of a special feeling quality or combination of feeling qualities. 

In attempting to deal with non-sensational or imageless proc- 
esses on the basis of our general theory regarding the nervous 
substrate of conscious processes, we shall avail ourselves of 
both the *kin9esthetic' theory and the 'condensed image* 
theory. To begin with, let us ask whether there is not some 
significance in the fact that certain of the imageless processes 
which have been enumerated by various writers can be readily 
named, while others cannot. Thus, some of them are clearly 
designated by being called 'likeness,' 'the feeling of 6w/,' 'ex- 
pectation,' 'louder than,' and so forth. On the other hand, 
Orth says of some of the conscious attitudes that they cannot 
be described or named; they can only be recognized; while 
Woodworth speaks of certain processes as being "nothing else 
than the particular feeling of the thought in question." 

Now, the process of naming is a motor response; an expe- 
rience is named when it calls forth a special reaction of the 
articulatory organs. When we get the experience that two ideas 
are opposed to each other the word 'but' springs to our lips 
without hesitation; when we recognize that one experience is 
like another, the word 'like' is instantly forth-coming; when 
we get a certain conscious attitude we describe it without delay 
as one of doubt. On the other hand, we do not adequately de- 
scribe the inkling of a forgotten name that haunts us by calling 
it an ! inkling': it is not like any other inkhng, and we have no 
word to express its differentiating character. 



196 MOVEMENT AND MENTAL IMAGERY 

If two processes (in our terminology, two movement systems) 
are associated with the same motor response, the great probabil- 
ity is that they are so associated by virtue of being essentially 
alike. We call many individual animals by the name *dog,' but 
we do so because of certain features that are identical in them 
all. It would therefore seem probable that if we promptly and 
unhesitatingly use the word 'but* when two conscious proc- 
esses are in a relation of opposition, no matter what the na- 
ture of the processes thus related may be, whether they are 
two colors or tw^o theories of the universe, the butness is due 
to a nervous process essentially the same in both cases. 

Further, if to every word that readily occurs to us as a name 
for an *imageless' process there corresponds a single character- 
istic nervous process; if all cases of 'ifness,' * butness,' likeness, 
difference, 'greaterness,' 'lessness' (we have not always the 
proper abstract noun), and so on depend, each class, on a single 
and always similar nervous process, which accompanies the vari- 
ous sensory excitations, visual, auditory, and so on, then there 
is good antecedent probability that these common factors are 
kinsesthetic in character. There is no other kind of sensation 
that so regularly accompanies other kinds as do the sensations 
produced by our own movements. Colors are not regularly 
accompanied by sounds, nor do smell, taste, or temperature 
sensations constantly accompany all other modalities of sen- 
sation: but we continually make movements of the eyes, the 
orgajis of speech, the fingers, or other parts of the body in con- 
nection with sensations of sight, hearing, taste, and so on, and 
these movements give rise to kinsesthetic excitations. As 
Beaunis (9) has said: "Muscular sensations enter not only into 
our sensations, but into perceptions, ideas, sentiments, emo- 
tions, in a word, into the whole psychic life; and from this point 
of view it may be said with truth that the sense of movement is 
the simplest and the most universal of psychic elements." This 
fact, which is apparent to every one, is one of the bases of our 
theory, according to which the whole play of conscious proc- 
esses def>ends on the interaction of movement systems, and the 



BIAGELESS PROCESSES 197 

connections between ideas are based on the connections be- 
tween kinsesthetic pathways and motor pathways. 

Let us suppose, then, that the more readily namable an 
imageless process is, the more it tend^ to have a kinsesthetic 
basis: the less readily namable it is, the more it involves proc- 
esses of other modalities, less constant factors in experience. 

If, then, some of the imageless processes are kinaesthetic in 
their origin, why should they be thought of by so many psy- 
chologists as non-sensational? Just what does the term * non- 
sensational' mean.'' 

A kinaesthetic process is recognized and identified by intro- 
spection as a sensation when it is referred to a definite 'point in the 
body; this reference involving, of course, the excitation of cer- 
tain motor responses appropriate to the particular locality con- 
cerned. Now, as we have seen, individuals differ a good deal 
in their habits of reacting to their own kinsesthetic excitations: 
some persons, Strieker and Titchener, for example, with skill 
in attending to the sensations from their own movements, 
might therefore be expected to call certain processes kinses- 
thetic sensations when other persons were unable to localize the 
processes in question. Further, many of the kinsgsthetic proc- 
esses which occur in the organism none of us have formed the 
habit of locahzing, because we have not needed to do so. 
Whether we form the habit of attending to the location of an 
excitation or to some other characteristic of it depends on 
practical considerations- In the case of the large majority of 
kinsesthetic excitations, attention has been directed, not so 
much on the location of the muscles involved, as on other char- 
acteristics of the excitations: for instance, their duration, 
whether they involve a change from a previously existing atti- 
tude, whether they are mutually inhibitory, and so on. Since 
it is only when we locahze a kinsesthetic process that we call it 
a sensation, and since we have seldom been interested in localiz- 
ing our kinsesthetic processes, it is not surprising that many 
processes which are based on kinsesthetic excitations do not 
reveal themselves to consciousness as sensational (145). 



198 MOVEMENT AND MENTAL IMAGERY 

Further, it would seem natural to suppose that two condi- 
tions notably influence the readiness with which a combina- 
tion of kinsesthetic excitations can produce conscious effects 
that are analyzable by introspection. Or, to put the matter in 
simpler language, there are two conditions which, when a num- 
ber of muscular contractions occur at the same time, make it 
harder for us to locate the exact muscles that are concerned. 
The first of these is the frequency with which the muscles in 
question have acted together in the past. If two motor re- 
sponses invariably accompany each other, we naturally cannot 
attend to them separately. And if their invariable cooperation 
is secured by innate connections between their motor path- 
ways, if, that is, their movements form an innate system, we 
cannot hope to discover by introspection the complexity of the 
system. 

Secondly, since the analysis of a kinsesthetic fusion means 
the reference of the various kinsesthetic excitations that make 
it up to different points in space, the more varied the actual 
spatial position of the muscles involved, the more hope there is 
of such analysis. This means that a movement system which is 
widely diffused through the body will stand a better chance of 
being analyzed than one that is limited to a smaller local range. 

Now, there are certain imageless or relational processes which 
seem, if sufficient time is allowed them to develop, to pass over 
naturally into processes that involve a rather wide and general 
bodily disturbance. It is concerning the analyzability of these 
processes that the introspective testimony of different authori- 
ties most diverges. Examples are the * feeling of hui,^ which 
develops into the unpleasant * conscious attitude' of confusion 
or contradiction; and the * feeling of unexpectedness,' which 
passes over into the emotion of surprise. Whether these experi- 
ences are regarded as simple and unanalyzahle, or as the reverse, 
depends on whether one is thinking of them in their contracted or in 
their expanded form. Thus, when Titchener says of the feeling 
of * but,' " I do roughly localize it and I can roughly analyze it 
into constituents" (137, page 187), one may surmise that it 



IMAGELESS PROCESSES 199 

is not the 'momentary * feeling of but* which he has in mind 
so much as the conscious attitude of bafflement or confusion into 
which the * f eehng of but ' may develop. This is a diffused motor 
attitude, and being diffused, stands a better chance of having 
its component excitations localized. 

There are other namable imageless processes, whose nam- 
ability, if I may coin the word, strongly suggests the existence 
of a kinsesthetic basis for them, which do not develop into 
analyzable conscious attitudes. It is therefore not possible to 
prove from introspection that they are kinsesthetic, but it is 
equally impossible to prove from introspection that they are 
not kinsesthetic. When we remember that only under certain 
restricted conditions can we expect to analyze a kinsesthetic 
fusion and, by localizing the various excitations which it in- 
volves, to realize introspectively their kinsesthetic character, 
we are not justified in denying that a certain conscious experi- 
ence has a kinsesthetic basis because introspection furnishes 
no evidence of the fact. 

We shall, therefore, assume that all the namable relational 
or imageless processes are based on fusions of kinsesthetic ex- 
citations, proceeding from certain definite and characteristic 
systems or attitudes. When, in the interplay of movement 
systems which is constantly going on, certain emergencies 
arise, certain characteristic motor attitudes are produced. Some 
of these have a tendency to develop and diffuse themselves 
until they produce in consciousness analyzable organic atti- 
tudes like the emotion of surprise or the conscious attitude of 
doubt; others have not this expansive tendency. These latter 
cannot be described, although they can be named. Our object 
in what follows will be to investigate, for a number of namable 
processes of both classes, the nature of the situations which 
produce the characteristic motor attitudes; and for processes 
of the first class, to point out the nature of the analyzable atti- 
tudes into which they may develop. 

Perhaps the commonest and functionally the most funda- 
mental of all these motor responses accompanying certain hap- 



200 MOVEMENT AND MENTAL IMAGERY 

penings in the interaction of movement systems is that which, 
apparently, may accompany any sudden shift of motor excita- 
tion, provided that attention is directed to the relational or 
kinsesthetic aspect of the process; that is, provided that motor 
responses to this aspect are called forth either by the activity 
of the movement systems representing the * context' (constel- 
lation) or by the influence of the activity attitude representing 
a problem idea. The consciousness accompanying a sudden 
shift of motor excitation is the feeling or awareness or conscious- 
ness of difference. Suppose that a certain tone is sounded, and 
after an interval the same tone is given again. The second oc- 
currence of the tone finds its motor response in greater readiness 
than the first occurrence did, through that tendency to spon- 
taneous recurrence on which the memory after-image is based. 
The memory after-image need not be actually present in con- 
sciousness : we can hear the second tone and judge it to be the 
same as the first without having a memory after-image of the 
first tone and consciously comparing it with the second tone. 
But the motor readiness on which the memory after-image is 
based must be in some degree present, or the judgment *like' 
cannot be made. Suppose, now, that the second tone is not 
like the first. There then occurs a sudden shift of motor excita- 
tion from the recurrent resp>onse for the first tone to a different 
response for the second tone, and this shift is the cue for giving 
the verbal response * different.' There is some reason for think- 
ing that the judgment of likeness is made when there is absence 
of any ground for the judgment * different,' and that the latter 
is the positive experience. Hay den (49), experimenting with 
lifted weights, reports this with certainty: the judgment *like' 
occurs in the absence of any criterion for another judgment. 
Wolfe (155), working with tones, says that likeness is judged 
better than difference: this is a result that would occur if the 
observers, whenever they were in doubt, that is, not sure of a 
difference, said *like.' Since such judgments would be correct 
when the tones were actually alike, the number of correct judg- 
ments of likeness would naturally be increased. Whipple (151) 



IMAGELESS PROCESSES 201 

thus explains the greater number of correct *Hke' judgments in 
his experiments with tones. 

The attitude which corresponds to the feehng of difference 
has Httle tendency to develop into a more diffused and analyz- 
able attitude. The case is otherwise when a more or less def- 
inite expectation exists; when the object attended to is not only 
different from the one attended to just previously, but different 
from what was expected. Expectation is even in its lesser de- 
grees based on a bodily attitude that allows of considerable 
analysis. It very clearly involves for introspection a certain 
static attitude, giving rise to strain sensations; in fact, we com- 
monly speak of strained expectation. This attitude is modi- 
fied according as the expectation is wholly indefinite, wholly 
definite, or partially determined. We may be, that is, in a 
state of expectation of we know not what; or we may be ex- 
pecting a particular something; or we may expect one of sev- 
eral definite possibilities. When expectation is wholly indefi- 
nite, it would not seem to differ from the attitude of strained 
attention, of being on the alert. When it is absolutely def- 
inite, along with the attitude of strain there are already ex- 
cited the tentative movements which are the specific response 
to the stimulus awaited: thus, if we are watching for the waving 
of a white flag as a signal, we are already making responsive 
movements proper to that stimulus, such, for instance, as say- 
ing * white' to ourselves. These tentative movements may or 
may not be accompanied by an image of the object looked for. 
If, in the third place, expectation is of several possibilities, there 
is infused into the attitude of strain an attitude of hesitation or 
doubt. This attitude occurs whenever a certain movement sys- 
tem suggests incompatible movements alternately; we waver 
between the different possibilities. 

Now, the experiences of difference and of unexpectedness 
approach each other most closely when a person is told before- 
hand that he is to be given a stimulus that will either be like a 
particular one that he has had before, or be different from it. 
In this case he has set up a partially determined expectation 



202 MOVEMENT AND MENTAL BIAGERY 

attitude. He has the possibihty that the coming stimulus may- 
be Uke the former one, and the possibihty that it may not : he 
makes the tentative movements adapted to the reception of 
the former stimulus, which perhaps call up an image of it; 
but these movements are not so marked and so uninterrupted 
as if the expectation were wholly definite, and the attitude of 
hesitation or doubt is present. When the expected stimulus 
comes, if it is unlike the former one, the shift of kinsesthetic 
excitation is not so marked as if the expectation of a repe- 
tition had been absolutely definite, and hence the experience 
of difference is not so marked. The more definite the expec- 
tation, the greater the tendency of an unexpected stimulus to 
give rise to a widespread bodily attitude, which may be the 
basis of the unpleasant affective experience of irritation at the 
* incorrectness ' of the unexpected stimulus. The general bod- 
ily attitude of * surprise' occurs whenever there is a sudden 
and very marked shift of motor response, whether the pre- 
ceding attitude has been one of expectation or not. I may be 
surprised at a knock on the door when I am sitting in idle rev- 
ery. The attitude of irritation at wrongness or incorrectness 
gets its intensity, not from the degree of shift of motor atti- 
tude required, but from the steadiness and definiteness of the 
preceding expectation. A very slight mistake in some one's 
rendering of a familiar poem may give us the irritating feeling 
of incorrectness, an attitude which certainly does not owe its 
intensity to the fact that we have to disturb ourselves to at- 
tend to the new wording, but arises from the very definite 
way in which the movement system corresponding to the cor- 
rect rendering was already in process of excitation. 

The feeling of hut, as has already been said, belongs to the 
class of imageless processes that naturally develop into analyz- 
able attitudes. It resembles the * feeling of difference' in not 
involving any expectation, and the experience of incorrectness 
in being capable of developing into a more marked and gen- 
eralized organic disturbance than the experience of difference 
can evolve. It would seem to occur whenever two movement 



IMAGELESS PROCESSES 203 

systems, developing simultaneously and on the basis of asso- 
ciative dispositions connecting them with each other, reach the 
point where dispositions of equal strength tend to excite in- 
compatible movements. This occurrence appears to give rise 
to a definite and characteristic motor disturbance, in its lighter 
degrees reflected in consciousness as the 'feeling of but'; in 
its more developed and diffused state becoming the disagree- 
able conscious attitude of puzzle or confusion. 

Nearly if not quite identical with the attitude of confusion 
is the attitude of uncertainty. Broadly speaking, we feel the 
attitude of certainty when an associative disposition works 
promptly and without interference from other dispositions ; that 
is, when there is no inhibition from incompatible movements. 
Muller (89) has given an excellent discussion of certainty 
with regard to the recall of memory ideas: the chief criteria 
of certainty that the idea recalled is correct are, he says (1) 
the way in which the idea presents itself, whether alone or 
accompanied by other possibilities; (2) the promptness of the 
reproduction; (3) the distinctness and vividness of the idea; 
(4) the completeness of its detail; (5) whether it belongs to a 
modality in which we are accustomed to have accurate images. 
These bases for certainty in our judgments of the correctness 
of memory ideas are substantially the same as those of our cer- 
tainty in regard to any kind of judgments: if the associative 
dispositions work quickly and without conflict from incom- 
patible dispositions we are thrown into the kinsesthetic-organic 
attitude of certainty; if not, the attitude of uncertainty occurs. 
//, although, unless, are all words whose stimulus, so to speak, 
is an attitude produced by the occurrence of incompatible 
motor excitations. 

The feeling of hnownness or familiarity is another * image- 
less' process which readily passes over into an analyzable 
attitude. It is closely related, of course, to the * feeling of like- 
ness,' and in many experiments on recognition the experience 
that is obtained is not 'knownness' but 'likeness.' The differ- 
ence between the conditions for the two experiences is that, to 



204 MOVEMENT AND MENTAL IMAGERY 

make the judgment *like,' one must refer to a particular past 
experience, while to judge that a thing is known, that it has 
been experienced before, requires no such definite reference. 
That is, a thing is known if it has been experienced somewhere, 
at some time, in the past; it is like if it has been experienced in 
a certain definite setting, either recently experienced or now 
recalled. When the material for recognition experiments is 
simple and of a sort that has often been experienced before, 
as, for instance, a musical tone, then the judgment made re- 
garding it will be that of likeness or difference: the tone has 
often been heard before in many different settings, but the 
question is: Does it or does it not resemble one heard a few 
moments ago? When the material is more complex, like a 
photograph, or less frequently experienced, hke a peculiar odor, 
the judgment is that of knownness or unknownness: since 
the face or the odor is not a common element in experience, 
the question is: Have I ever encountered it before? 

Now, obviously we do not make the judgment * known* 
every time we encounter a thing we have met before. In that 
case we should be making it at every moment of our lives: I 
should pause to recognize my typewriter and my chair on 
coming into my study, instead of instantly proceeding to make 
use of them. We recognize the known only in the midst of the 
unknown. Titchener (138) uses the example of a man's sitting 
in a street-car and glancing at the faces opposite until he sees 
one that * looks familiar* to him. Now, such an experience as 
this can be described in terms of our theory somewhat as fol- 
lows. There are successively active in the man's cortex certain 
rather large movement systems, each representing one of the 
faces opposite. These systems, so long as they act as wholes, 
fail to set any further systems into activity : they have no asso- 
ciative tendencies, they suggest nothing. This suspension of 
associative activity gives rise to a peculiar general motor 
response, which in its stronger and more diffused form may be 
described as a feeling or conscious attitude of strangeness, 
and in some individuals may become a highly unpleasant 



IMAGELESS PROCESSES 205 

emotion. So far as it can be introspectively analyzed, it would 
seem to contain much muscular strain. When, however, the 
familiar face is attended to, the movement system which it 
involves begins to set into activity associative dispositions, 
although these may be too weak to produce actual recall. 
Nevertheless, the suspension of associative activity is relaxed, 
and with this the attitude of strangeness gives place to the 
attitude of familiarity, which Titchener has called * a weakened 
emotion of relief,' although there must be something specific 
about it to distinguish it from other cases of relief. In any case, 
the familiarity or knownness feeling may be thought of as 
based on a peculiar attitude, tending, as it becomes stronger 
and more diffused, to pass over into a more or less analyzable 
experience into which bodily relaxation clearly enters. The 
natural course of events, when we recognize an object as known, 
is to proceed to the recall, in some kind of imagery, of the 
circumstances under which we have met it before. As the 
associative dispositions which it sets into activity become 
more numerous and more active, we begin to have imageless 
processes of the unnamable type, * inklings' of the former 
setting of the recognized experience. Finally, these give place 
to definite imagery and the recognition process is complete. 

Other attitudes which in their fully developed form are 
more or less analyzable are those connected with judgments 
of the intensity and duration of stimuli. We have already 
suggested that the intensity of a sensation is an experience 
based on the presence of a more or less diffused motor response, 
giving rise to organic and kinsesthetic excitations. The fact 
that intensity can be called, as it is by Ebbinghaus,^ a 'com- 
mon property ' of sensations, implying that intensity is always 
the same kind of experience no matter what it is the intensity 
of, that the loudness of a sound is in some degree the same 
kind of experience as the hardness of a pressure, strongly 
indicates that it has a kinaesthetic basis. 

Our absolute judgments of high degrees of intensity are 
^ Grundziige der Psychologie (Leipzig, 1902). 



206 MOVEMENT AND MENTAL IMAGERY 

probably based on the degree of diffusion of the stimulus 
energy through the motor pathways of the body. We can by 
introspection describe the attitude characteristic of high in- 
tensity as a kind of general muscular shrinking, which is at 
the same time a withdrawal and a summons of the muscular 
forces of the body to endurance, and we can more or less local- 
ize the kinsesthetic and organic excitations thus produced. 
In the case of absolute judgments of very slight intensity, 
another attitude is apt to be the basis of the judgment: a gen- 
eralized muscular response, namely, which is not the result of 
the overflow of stimulus energy, but rather due to the strain 
that accompanies the effort to attend and to prevent distrac- 
tion which will cause the stimulus to lose its effectiveness. 
The words used to express our judgments of absolute inten- 
sity are significant. The words for high intensities tend to 
vary according to the kind of sensation that is meant: thus 
we say 'loud' for a sound, 'bright' for a color, 'strong' for a 
pressure or a smell, to designate intense sensations; but for 
weak sensations the variety is less. Neither a color nor a smell 
nor a pressure can be 'loud'; but a sound and a touch can 
both be 'soft'; a sound, a color, a smell, can all be 'faint.' This 
is very likely due to the fact that in weak sensations the specific 
quality is poorly discriminated. 

Judgments of relative or comparative intensity are, of course, 
a special kind of judgments of likeness or difference. If we lift 
two weights in succession, and judge the second to be heavier 
than the first, we are judging first of all that they are different, 
and secondly, that they differ in respect to intensity. We have 
in this case, then, first, the sudden shift of kinsesthetic excita- 
tion which is the basis of the judgment 'different'; this is 
modified into the judgments 'intenser' or 'weaker' according 
to the felt character of the general motor response. Of course 
practice in making such judgments of the relative intensity 
of stimuli might result in producing the verbal response 
* stronger' or 'weaker' as the direct effect of the stronger or 
weaker excitation of the sensory centre immediately acted on 



rVIAGELESS PROCESSES 207 

by the stimulus. But in this case the judgment would be auto- 
matic, and there could be no question of the presence in con- 
sciousness of any special content representing the intensity. 
When the judgment is made with hesitation, the basis of con- 
sciousness of the * relational element' * stronger than,' * weaker 
than,' which is recognized as an experience of the same quality, 
no matter what the sensations compared, is indicated by this 
very recognition of its uniform character to be kinaesthetic in 
its source. 

Duration is another 'common' or * generic' property of 
sensations: temporal 'long' and * short' are felt to be the 
same kind of experience, no matter what kind of sensational 
content fills the duration. For a theory as to the kinsesthetic 
basis of temporal judgments we may refer to Wundt (160), 
since there are good reasons for thinking that what he calls 
* feelings of strain and relaxation' are wholly kinsesthetic 
in their origin. A long-lasting stimulus produces a peculiar 
attitude of strain: its cessation an attitude of relaxation. 
Wundt distinguishes between the feelings of strain and relaxa- 
tion on the one hand, and kinsesthetic sensations, which he 
says also enter into temporal judgments, on the other; but if 
one takes the ground that a process may be sensory in its 
physiological basis and yet not analyzable into localized 
sensations, it is easy to interpret Wundt's 'feelings' as unana- 
lyzed kinsesthetic fusions, and his 'kinsesthetic sensations' as 
kinsesthetic processes which can be introspectively located. 

To suppose a kinsesthetic basis for spatial judgments is in 
principle easy, whatever problems may arise in the working 
out of the details of such an hypothesis. So far as the judg- 
ments are quantitative, duration judgments play an impor- 
tant part in them. 

There are, of course, three kinds of 'size,' corresponding to 
the three dimensions of space: there is the length of a line, the 
area of a surface, and the cubic size of a solid. The most 
obvious basis for judging a line as long or short consists in 
judging the duration of the hand and eye movements made in 



208 MOVEMENT AND MENTAL IMAGERY 

exploring it, whether these movements are fully performed or 
only tentatively performed. It must be remembered, though, 
that the movement systems involved in exploring objects 
that are extended in space have a peculiar characteristic: 
namely, that the movements they involve may be made 
equally well in either of two opposite time sequences: they 
form, as we have seen (pages 14-15) opposite, irreversible, suc- 
cessive movement systems. When the kinsesthetic sensations 
from such a system, whether the movements are fully or only 
tentatively performed, are of considerable duration, the judg- 
ment *long' is suggested with regard to a line: when they are 
of brief duration, the judgment * short' is suggested. The 
relative judgments * longer than,' 'shorter than,' involve the 
experience of difference, plus the experience of long or brief 
duration of the kinsesthesis. The fact that the words *long' 
and * short' are used indifferently of lines and of durations 
points clearly to the common character of these experiences. 

In the case of a surface whose area is judged large or small, 
a number of linear movement systems are linked together in 
a system of a higher order. A surface may be explored from 
right to left, or from left to right; from above downward or 
from below upward; and obliquely back and forth in any 
direction. The duration of the kinsesthetic excitations from 
these movements, whether of the eye or of the hand or both, 
is the basis of the judgments of the size of the surface. In like 
manner judgments of solid dimensions depend on sensations 
from the hand and eye positions needed to examine or explore 
the object: the amount of convergence and accommodation 
of the eyes; the (extension of the fingers and arms needed to 
surround the object. 

Nearly all of the 'relational' or 'imageless' processes we 
have thus far considered have been of the type which under 
certain circumstances develops into a more or less analyzable 
conscious attitude; and for this reason we have been able to 
indicate from introspection something as to the nature of the 
attitudes which underlie them. Thus, we have been able to 



EMAGELESS PROCESSES 209 

suggest that the experiences of but and if involve strain and 
suspended movement; that famiharity involves relaxation; 
that high intensity involves a kind of shrinking; and so on. 
These descriptions have been extremely imperfect, but they 
have been perhaps sufficiently recognizable to make plausible 
the theory that there really are motor attitudes underlying 
the namable imageless processes. The so-called logical rela- 
tional processes are less prone to develop into analyzable 
attitudes. The experience or feeling of contradiction^ indeed, 
represents a fundamental logical relation, and it, as we have 
seen, quite readily develops into an attitude that can be ana- 
lyzed with a fair degree of success. The experience of causality 
can best be conceived as dependent upon a peculiar attitude 
which may be called the *why' attitude. I come into my sit- 
ting-room and see a tall vase lying on its side on the table. 
Instantly I fall into the attitude, *Why?' *How?' Now, this 
attitude on my part is not inevitable. The Kantian philoso- 
phers said that the principle that nothing happens without a 
cause is a fundamental, unescapable category or form of all 
thinking. They did not mean, of course, that thinking itself 
is imescapable. I may perfectly well, if my attention is occu- 
pied with something else, or even if it is relaxed and drowsy, 
gaze unthinkingly and uninquiringly at the overturned vase. 
Even if I attend to the vase and to its overturned position, the 
attitude *Why.^' is not inevitable: I may occupy myself rather 
with the future, the immediate practical consequences of the 
overturning, than with its cause. I need to be in a kind of 
backward-looking attitude to ask *Why?' 

We have assumed that our experience is based on the inter- 
play of movement systems. Now, the relation of cause and 
effect concerns the sequence of two movements which not only 
form a successive system through having occurred in a certain 
time sequence on many occasions, the cause preceding the 
effect, but are linked into a closer unity through being asso- 
ciated with a simultaneous system, their meaning. In the 
chapter on "Simultaneous Movement Systems," it will be 



210 MOVEMENT AND MENTAL IMAGERY 

remembered, we saw that when a successive movement sys- 
tem — a series of words in a sentence, for example — is con- 
nected with a simultaneous system, — for instance, the mean- 
ing expressed by the sentence, — the successive system gains 
such unity that its latter parts, given alone, may through the 
medium of the meaning recall the earlier parts. Such a unified 
successive system is formed by a cause and an effect; on the 
effort to complete it rests the tendency to seek for a cause. 
Mere time sequence, the mere observation that B follows A, 
is not a sufficient foundation for the causal relation: we need 
to feel that the two phenomena are essentially one, the work- 
ing out of a single meaning, that is, associated with a single 
simultaneous movement system. 

The w^eaving in and out of movement systems with their 
attendant imagery is every now and then interrupted by the 
incursion of an outside stimulus, a change in the outside world. 
Many of these changes we have anticipated and expected; 
that is, the movement systems to which their motor responses 
belong are already in activity. Others are unexpected: the 
motor responses to which they give rise are not a part of the 
systems functioning at the time they occur. Now, the effect 
which these unexpected stimuli produce depends on circum- 
stances. If there are in action rapidly developing movement 
systems that are actually incompatible with the motor re- 
sponse belonging to the unexpected stimulus, it may go un- 
attended to. If it is attended to, since it and the systems al- 
ready on the field have no connection, and cannot together 
determine the following systems, there occurs a stoppage in 
brain activity. What follows the stoppage depends largely 
on the individual traits of the person. A weak or a lazy mind 
will, after a moment or two of gaping wonder, leave the dis- 
connected phenomenon unexplained. A person who has a 
strong tendency to full rather than tentative movements, 
what we call a man of action rather than reflection, will pro- 
ceed to make movements appropriate to the new stimulus, 
without any attempt to explain it; wiE, for instance, pick up 



IMAGELESS PROCESSES 211 

the vase and place it in its proper position. It takes a person 
of a naturally thoughtful and energetic mind to be seized by 
the problem of explaining the unexpected stimulus. To ex- 
plain it means to reconstruct in thought the experience of a 
person to whom the phenomenon would not have been unex- 
pected: in other words, to set in action the system of tentative 
movements that would lead naturally to the thought of just 
such a phenomenon, and hence must have been involved in the 
experience of one in a position to witness all the events which 
led up to it. To be thus thoughtful and energetic, one must 
be so constituted that a check in the systems of tentative 
movements is even more disturbing than the checking of a 
full instinctive movement; and so constituted that the ac- 
tivity attitude, on which prolonged intellectual work depends, 
alternates with relaxation at just the intervals most favorable 
to its long association with a given problem. 

The idea of a cause is an idea that can put an end to the atti- 
tude *Why.?' or, in our terminology, it is an idea based on a 
movement system that is capable of putting an end to the atti- 
tude 'Why?' And such a movement system is one that forms 
the earlier section of a successive and irreversible movement 
system, whose later section is constituted by the effect, and 
which is held together by its association with a simultane- 
ous system. The *Why?' attitude is occasioned by the tend- 
ency of the latter half of a successive system to complete 
the whole system, and the temporary checking of this tend- 
ency. I see that the casement window behind the table on 
which the vase stands, though closed now, is not latched, and 
I immediately think of the probability that it blew open, and 
that the breeze thus admitted upset the vase. The ideas of 
the breeze and of the overturned vase, on the basis of frequent 
experience, form a successive movement system whose order 
is determined: wind and displaced objects have always oc- 
curred in just this sequence: never has a displaced object been 
followed, rather than preceded, by the blowing of the wind. 
In most cases, moreover, the system which is completed by 



212 MOVEMENT AND MENTAL IMAGERY 

the idea of the cause is a very large one, so that the order of 
events within it is determined, not merely by the observed 
sequence of the two phenomena called * cause' and * effect,' 
but by many other phenomena. I conclude that the breeze 
may have overturned the vase, not merely because I have often 
observed objects being blown over, but because this is a world 
in which an effect of this kind must have been produced by 
the application of a force in a certain direction and manner. 
It is absolutely essential to the conscious experience of the 
relation of causality that it shall be accompanied by the occur- 
rence of a particular movement system which puts an end to 
the *Why?' attitude; which attitude is occasioned whenever 
there is an obstacle in the way of the completion of a unified 
successive movement system whose latter half is given. 

In the case of the logical relations of subordination and 
supraordination and of whole and part, we have attitudes that 
have apparently no tendency to develop into different and 
analyzable bodily disturbances. When we are aware, in con- 
sidering two ideas, that the one is an idea of a whole and the 
other an idea of a part of that whole, as when we think of 

* house* and *roof,' we are in some way aware that we are 
passing from a smaller movement system to a larger one in 
which the smaller one is contained, or vice versa. Since it is 
usually simpler and easier to think in terms of wholes rather 
than parts, the passage from part to whole is, as it were, a 
release into free activity of certain associative dispositions 
that were held in check while the part only was being attended 
to. In the case of subordination and supraordination, that 
is, of the relation between a genus and a species, or between a 
general idea and a concrete example, the more general idea 
also represents a smaller movement system than the less gen- 
eral idea. There are not so many elements involved in the idea 
'animal* as are involved in the idea * horse.* How, then, does 
the relation of genus to species differ from the relation of part 
to whole: what is the difference between passing from the idea 

* horse* to the idea * animal' and passing from the idea * horse' 



IMAGELESS PROCESSES 213 

to the idea *mane'? Clearly, to understand the relation of 
genus to species we must take into account, not only what the 
logicians termed the * intension ' of the concept, but also what 
they termed its * extension.' By * intension' is meant the quali- 
ties possessed in common by all the examples of the class which 
the general idea or concept represents. Thus, the intension of 
horse is composed of all the qualities belonging to all horses, 
and the intension of animal is composed of all the qualities 
belonging to all animals: evidently the intension is less, the 
more general the concept. The extension of a concept con- 
sists of all the individuals which belong to the class represented 
by the concept. Thus, the extension of horse is all the horses in 
existence, and the extension of animal is all the animals in 
existence. Evidently the extension is less, the less general the 
concept. Now, the extension of a concept would seem to con- 
stitute the type of movement combination which we have 
called a *set of movements,' as contrasted with a * system of 
movements.' We have a set of movements when a number of 
movements or movement systems are related only in that they 
all have a movement or small movement system in common. 
Thus, all the words which stand for opposites, like *dark,' 
Might,' * large,' * small,' *high,' *low,' belong to a set of move- 
ments connected simply by their common inclusion of the 
feeling of opposition and the word * opposite.' Movement 
systems which belong to the same set of movements are com- 
monly of about the same degree of complexity. Thus, when 
we pass from the idea of a whole to the idea of a part, while 
we go from a larger to a smaller movement system, in that the 
intension of the whole is greater than that of the part (there 
are more features belonging to a whole horse than to a mane), 
the two systems have about the same extension; that is, they 
put into readiness sets of movements, referring to individual 
horses and manes, of about the same size. On the other hand, 
when we pass from the idea of a species to that of a genus, while 
we again go from a larger and more complex to a smaller and 
less complex movement system, we at the same time pass from 



214 MOVEMENT AND MENTAL BIAGERY 

a movement system which tends to set in readiness a com- 
paratively small set of movements (ideas of different kinds of 
horses) to one which tends to set in readiness a larger set of 
movements (ideas of different kinds of animals). 

The study of the possible physiological basis of such proc- 
esses as are involved in the *feeHngs' or * awarenesses ' of the 
relations of subordination and superordination, whole and 
part, strongly suggests that they are attitudes which in some 
way depend on the number and complexity of the movement 
systems which a given system tends to set into action. What 
would be the difference between the activity of associative 
dispositions, that is, kinsesthetic processes, involved in the 
extension of a concept and the activity involved in its inten- 
sion? The principal difference seems to be this: the move- 
ments which represent the intension are linked together in a 
true simultaneous movement system: each one of them is 
connected by associative dispositions with all the others. The 
characteristics which make up our idea of the meaning or inten- 
sion of the word ' tree, ' are all equally necessary to the system 
as a whole. But the movements which represent the extension 
are not so linked: an individual tree has features, which must 
be involved whenever it is thought of as an individual, that 
are actually incompatible with those of other individual trefes. 
In the case of the simpler concepts we can think of the inten- 
sion of the concept in a single generic image, so unified is the 
movement system involved in the intension. But the exten- 
sion of a concept can never operate as a single whole or system 
to determine the direction of associative dispositions. In the 
extension, thought as it were scatters; in the intension, it 
grasps. 

When we pass in thought from a concept of less intension 
to one of greater intension, as when we pass from the idea of 
*tree' to the idea of *elm tree,' the movement system is en- 
larged : an elm tree is a tree plus certain features that distin- 
guish it as an elm. At the same time the unity of the effect is 
not disturbed: in other words, no mutually incompatible reac- 



IMAGELESS PROCESSES 215 

tions tend to be excited. When the change is in the opposite 
direction, and we pass from the less general, from *dog,' let us 
say, to * animal,' the movement system is restricted in its scope: 
certain associative dispositions that were previously active are 
now inhibited. On the other hand, if we consider the processes 
underlying extension, when an idea of less extension, such as 
*dog,' gives place to one of greater extension, such as * animal,* 
there is an increase in the number of incompatible movements 
that are set up, alternately, of course: thoughts and images 
connected with a variety of individual dogs may give place 
to thoughts and images connected with the much greater 
variety of animals. That the * feelings' of greater and less 
extension and of greater and less intension are due to peculiar 
motor reactions occasioned by these differences in the behavior 
of movement systems, but not further describable because 
they do not, like some of the other attitudes we have assumed 
as the basis of imageless processes, develop into more wide- 
spread bodily disturbances, would seem the most plausible 
explanation of them. 

After this survey, all too hasty and superficial, of some of 
the imageless processes that can be named, and thus may be 
presumed to have a kinsesthetic basis which is for each process 
more or less uniform, let us turn to the other class, those which 
cannot be named. The inkling of a half -forgotten name is 
something individual; it is not like any other inkling, and yet 
it is not recognizably sensational. The meaning of a word, 
while it may often be an image, is quite as often something for 
the time being at least imageless; but it is something specific 
— as Wood worth says, "nothing else but the particular feeling 
of the thought in question.'* The physiological basis for image- 
less processes of this kind must be different in each case: it 
cannot be any form of general motor attitude. 

Imageless thoughts of the non-namable kind seem to occur 
under two different conditions. On the one hand, as in the 
case of an 'inkling,' they occur when something is blocking the 
associative processes. I am inclined to think that they do not 



216 MOVEMENT AND MENTAL IMAGERY 

occur when associative processes are intrinsically weak, but 
rather when they are partially interfered with by incompatible 
processes. We can practically always distinguish introsj>ec- 
tively between the case where we have wholly forgotten a 
name or a word and have no chance of recovering it, and the 
case when it is almost on the tip of our tongue and is worth 
trying for. In the former case the associative processes are 
weak and ineffective; in the latter case, when we have an ink- 
ling, they are fragmentary. The state of things in the latter 
case may be conceived somewhat as follows: a fairly complex 
movement system is set into activity, but some of its parts 
are wholly inhibited by certain incompatible innervations 
already on the field. The result is that the system is fragmen- 
tary, and the associative dispositions which depend on the 
system as a whole are prevented from being excited. The 
fragmentary character of an inkling is often revealed to intro- 
spection; we can be sure at times of the general rhythm of 
the word or phrase we are looking for, or of its first letter. I 
was once trying to recall a technical term in marine insurance, 
* general average.' Something was wholly inhibiting the sec- 
ond word: the first word was active, apparently, just enough 
to set into action the associative dispositions connecting it 
with the word * special'; thus, for a long time I could get no 
further inkling than a two-word rhythm and the word * spe- 
cial,' which however was naturally unable to suggest * aver- 
age.' 

On the other hand, imageless processes apparently occur 
when thinking is especially rapid and easy. We take a mental 
glance at a whole field of knowledge, and the glance occupies 
but an instant, yet we know what we have glanced at. Thus 
Kulpe, observing in BUhler's thought experiments, says that 
he had momentarily the whole development of ancient skep- 
ticism, in three periods, before him in outline. In such cases 
the imageless character of the thought certainly seems most 
plausibly explained as due to the condensation of the imagery; 
to the fact that many image processes occur simultaneously 



IMAGELESS PROCESSES 217 

and without the analysis which would require time to perform. 
Biihler, it is true, rejected what he termed the condensation 
theory of thoughts, that they are condensed and abbreviated 
sets of ideas, on the ground that such a condensation ought 
not to make them lose all the characters of images, such as 
intensity and quality. But if we remember that for a sensa- 
tion or an image to possess quality and intensity for introspec- 
tion requires attention to be directed to those aspects; that is, 
requires specijSc motor reactions to be made to them; and that 
this could not be done simultaneously for a great number of 
images, we must admit that a loss of the characteristics of 
images is precisely what we should expect of a condensed and 
telescoped train of images. When an extremely complex move- 
ment system, involving possibilities of a great variety of 
images, functions as a single whole in calling up other move- 
ment systems, as when Klilpe thought about ancient skepti- 
cism in an instant of time, the consciousness produced by 
slight delay in its functioning will be a composite of elements 
each of which alone would be a recognizable image with the 
proper characters of an image; the whole mass of which, how- 
ever, will certainly be imageless. 

Besides condensation as a cause of the loss of the image 
characters in thoughts, we have the increasing prominence of 
the kinsesthetic elements in images as the movement systems 
on which they are based become more fully organized. It will 
be remembered that a movement system is formed when a 
number of movements, each of which has originally a stimulus 
of its own, come to be dependent for their excitation each on 
the kinsesthetic processes resulting from some other movement 
in the system. Thus, every motor pathway in a movement 
system has connections with two sensory pathways, one that 
of its original stimulus, which may have been visual, auditory, 
or of any other modality; the other, that of its kinsesthetic 
stimulus; and the consciousness that accompanies any delay 
in its functioning is a fusion of kinaesthetic sensation with the 
centrally excited sensation or image of its original stimulus. 



218 MOVEMENT AND MENTAL IMAGERY 

Now the more thoroughly organized the system, the less delay 
is likely to occur, and the more consciousness tends to be 
restricted to the kinsesthetic processes, which are necessary, 
rather than to extend itself to the images of other modalities. 
Thus Book (13) found that in learning to typewrite processes 
of other modalities gradually gave way to kinsesthetic proc- 
esses. As a movement system becomes thoroughly organ- 
ized, then, its conscious accompaniment tends to become kin- 
sesthetic, and kinsesthetic fusions are for reasons which we have 
sufficiently indicated, often unlocalized and hence often un- 
recognized for what they are. To express the truth that every 
idea has both an imaged (anschaulich) and an imageless 
(unanschaulich) content, we should say that every idea has 
a non-kinsesthetic and a kinsesthetic content. "Every idea," 
says Koffka (63), "has its unanschaulich content, and this may 
occur alone without the anschaulich foundation with which 
it was originally united." I am not sure that I understand 
Woodworth's (158) doctrine of imageless perception, but 
when he says of the * mental reaction' which according to him 
constitutes * perception*: "It is something new, not present 
in the sensations, but theoretically as distinct from them as 
the motor reaction is. It adds new content which cannot be 
analyzed into elementary sensations; so that the sensory ele- 
ments which are often held to supply, along with the feelings, 
all the substance of consciousness, in reality furnish but a 
fraction of it, and probably a small fraction. Each perceptual 
reaction is specific and contributes specific content," he seems 
to me to mean exactly what I mean by the kinsesthetic com- 
ponent of every idea. Certainly, when he goes on to identify 
the * perceptual reaction' with form qualities, — that is, with 
the shape and size of spatial objects, the temporal form of 
rhythms, and the like, — he is ascribing to it precisely one 
of the functions of the kinsesthetic components of images. 
(It will be borne in mind that when I speak of the kinsesthetic 
or unanschaulich components of images, the kinsesthetic 
processes are themselves peripherally excited: the doctrine of 



IMAGELESS PROCESSES 219 

tentative movements requires that all kinsesthetic processes 
shall result from actual muscular contraction.) 

From our general point of view, finally, we can attack the 
problem of meanings and avoid McDougall's (73) conclu- 
sion that they form in themselves a refutation of the doctrine 
that association is fundamentally the association of move- 
ments. 

McDougall seems to think that the existence of meanings 
as imageless processes disproves a motor theory of association. 
But we have seen that a process may be imageless to intro- 
spection, and yet have the same kind of physiological basis 
as ordinary sensations. The fact is that an idea and its mean- 
ing are based on systems that are equivalent for associative 
purposes. The practical value of a word is that it, a compara- 
tively simple movement system, has the same tendencies to 
excite other movement systems that is possessed by what may 
be a much more complex movement system, its meaning. A 
meaning is not merely that which is suggested by a word: if 
this were so, then * black' might be the meaning of * white,' 
since the word * white' almost instantly suggests the word 
* black.' It is that which suggests nothing that the word itseK 
does not suggest. When we express a thought, and some one 
else attempts to express it for us, we say, *No; that is not what 
I mean,' the instant the speaker's words set up movement 
systems that are incompatible with those already active in our 
own minds, thus giving us the relational experience of con- 
tradiction. Obviously the same word may mean different 
things at different times, that is, in different contexts: obvi- 
ously the context helps to determine the associations it will 
call up. Obviously the same image may stand for a particular 
object or for a general idea: the same drawing of a triangle 
may mean an isosceles triangle or triangle in general, accord- 
ing as its associative tendencies are limited and directed, by 
the constellating effect of the context or by a directing idea. 
To say that the triangle means an isosceles triangle is the same 
thing as saying that its associative tendencies are identical 



220 MOVEMENT AND MENTAL IMAGERY 

with those of an isosceles triangle, and any incompatibility 
between them will be felt as a contradiction: to say that it 
means triangle in general, is to say that its associative tenden- 
cies will be identical with those of triangle in general, and only 
incompatibilities between these two sets of associative tend- 
encies will give rise to the attitude of contradiction. 



CHAPTER XI 

DISSOCIATION 

When any two movement systems go on simultaneously, 
as they may if they do not contain incompatible movements, 
the natural tendency is for associative dispositions to be set 
up between them. When two systems are successively set into 
activity, the natural tendency is for them to form a single 
successive movement system. It is natural for us, in recalling 
an event, to recall its setting or surroundings, and to recollect 
the events which immediately followed and preceded it. But 
there are certain circumstances under which the normal and 
natural formation of associative dispositions fails to occur. 

Let us consider some of these circumstances. (1) A person 
under great stress of emotion is interrupted by a call to the 
telephone on some trivial business : he answers the call intelli- 
gently and is then again overwhelmed by his emotional crisis. 
Later he has no recollection of the telephone call or of the 
appointment he made in reply to it. (2) A man is injured in a 
football game: he has later no recollection of the ten or fifteen 
minutes which preceded the injury. (3) A person is thrown 
into the hypnotic trance, and while in this condition he per- 
forms various actions at the suggestion of the operator: on 
coming out of the trance he cannot recall anything that oc- 
curred while he was in it. (4) A man finds himself unable to 
recall a perfectly familiar name. A careful introspective study 
proves that this name is associated with a disagreeable event, 
of which the man has been trying not to think. (5) A man is 
sitting with a pencil in his writing hand, and his attention 
centred on a book. In response to questions whispered in his 
ear, his hand writes a few appropriate words : on being recalled 
from his reading he has no recollection of the questions or of 
writing. 



222 MOVEMENT AND MENTAL IMAGERY 

These are all cases where movement systems which should 
normally connect themselves by associative dispositions re- 
main disconnected or dissociated. Four different conditions 
seem to be involved in them: in (1) and (2) the dissociation is 
apparently due to a general disturbance or shock to the 
organism; in (4) the disagreeableness of an experience seems 
to dissociate it from other experiences; in (5) concentrated 
attention appears to be responsible for the dissociation, and 
in (3) the conditions are those which produce the hypnotic 
trance. 

Why should strong emotion of any kind, including shock, 
interfere with the normal formation of associative disposi- 
tions .^^ An emotion is a movement system of the greatest pos- 
sible complexity. When fully developed it involves practi- 
cally every muscle in the body. Every bodily movement and 
every idea feel its effect, either in the way of excitation or 
inhibition. Now ordinarily, when one movement system in- 
tervenes upon another one, the interrupted system, while in- 
hibited for the time, remains in a state of readiness to be re- 
sumed. In Poppelreuter's (112) suggested experiment,^ where 
sentences from two different stories are read alternately, the 
interruption of one train of thought by another does not pre- 
vent the interrupted train from exerting its influence on its 
continuation. We do not hear the fourth or fifth sentence in 
story A as if we had never heard its predecessors: the two 
stories are both perfectly comprehended at the end. If, how- 
ever, the place of the second story were taken by a violent 
emotion, story A's effect would be quite obliterated. 

It seems most probable that when the two stories, read alter- 
nately, are thus connectedly understood; when the first sen- 
tence of story A forms associative connections with the second 
sentence of the same story, across the gap filled by the first 
sentence of story B, the reason is that the interruption has not 
been absolute. Some parts of the complicated movement 
system set going by the first sentence of story A continue in 
} See page 136. 



DISSOCIATION I 223 

activity, even during the interruption: such parts, namely, as 
do not involve movements incompatible with those of the 
first sentence of the interrupting story B. Now the more far- 
reaching and complex the movement systems started by story 
B, the less possible will it be for any portion of A's movement 
systems to remain active over the interval. This would explain 
why a strong emotion makes so complete an interruption, and 
prevents the formation of associative dispositions between the 
events which preceded it and the events which followed it. 
The emotions and shocks which thus dissociate are always 
sudden in their onset, and not themselves the natural outcome 
of what has previously been going on. And they are movement 
systems so far-reaching and complicated that no portion of the 
previously active movement systems can last over during the 
interval filled by the emotion. 

That an unpleasant emotion exerts a special dissociating 
effect apart from and unlike in its manifestations the dissocia- 
tion produced by any sudden and violent emotion is one of the 
facts brought to our attention by Freud. We tend, he argues, 
to avoid recalling unpleasant experiences to consciousness. 
This tendency may make it impossible to recall anything that 
is associated even in the most casual way with the unpleasant 
set of ideas. Thus Freud (39) reports that he unaccountably 
failed to recall, in a conversation on Italian art, the name 

* Signorelli,* and by careful introspection he unearthed the 
fact that the name was inhibited because its first two syllables, 

* Signer,' are associated with the word *Herr' through their 
meaning; 'Herr' has the sound of the first syllable of 'Herze- 
govina,' with which province Freud had at the time a very dis- 
agreeable association. To many of us this will seem far-fetched, 
but association with what is unpleasant and for that reason 
avoided in thought is very likely one of the actual causes of 
interference with the normal working of associative disposi- 
tions. To form an idea of how this effect is produced, we may 
first note that if a movement already belongs to a strongly 
formed movement system, it will enter with great difficulty 



224 MOVEMENT AND MENTAL EMAGERY 

into any system that contains incompatible movements with 
those of the first system. An example from my personal ex- 
perience will make this clear. I once had occasion to see almost 
daily a person named *Harkness/ who was a new acquaintance, 
a man of the intensely practical, traveling-salesman type, in 
the habit of declaring himself a self-made man, and implying 
suspicion of the value of a university education to one dealing 
with affairs, — in short, what would in the vernacular be 
called a * hustler.' I found it almost impossible to recall this 
person's name, and after Freudian seK-examination, I found an 
explanation undoubtedly far too simple to satisfy Freud. The 
name *Harkness' was uniquely and firmly established in a 
classical setting in my mind. Not only had I in my youth 
used Harkness's Latin Grammar, but my Freshman Latin 
had been studied under the direction of a teacher of pro- 
nounced personality, named Harkness. The whole atmosphere 
of my new acquaintance was so incompatible with that of the 
classics that I simply could not implant so classical a name in 
so imcongenial an environment. 

Now, if even a small and unimportant movement system, 
like the classical associations grouped around this name, could 
suffice, as I believe it could, to interfere with and weaken asso- 
ciative dispositions tending to connect one of its members 
with a new system incompatible with the old, how much more 
readily can a great and complicated system like what the 
Freudians term a * complex,' a system of ideas bound together 
by being connected with a strong emotion, produce such in- 
terference. The suppression of a complex — that is, of the 
ideas connected with a disagreeable experience — takes place 
through the presence of a stronger emotional or affective state 
of the opposite character. The normal attitude of a healthy 
individual is an attitude of cheerfulness. Now, an attitude of 
cheerfulness is an actual static movement system, involving 
certain innervations, and while it is maintained it will inhibit 
all incompatible innervations. A person in the attitude of 
cheerfulness is incapable for the time being of a depressing 



DISSOCIATION 225 

thought, for precisely the same reason that he cannot pro- 
nounce t and g at the same time: the movements involved are 
incompatible. "How long, oh healthy reader,'* asks James, 
*'can you now continue thinking of your tomb?" 

Complexes are suppressed, not simply in the case where 
strongly unpleasant ones come into conflict with a dominant 
attitude of cheerfulness, but whenever there is incompatibility 
between their movement systems and those dominant at the 
time. Thus, a complex may be interfered with because its 
emotions conflict with all that carefully acquired system of 
attitudes which we call * propriety': or an emotion may be 
suppressed because it is incompatible with the emotion which 
we know we ought to feel, and which we therefore do often 
feel, strongly enough at least to prevent the development of 
incompatible emotions. It is not surprising if, as the Freudians 
tell us, these cases of the interference of incompatible emotions 
result in profound bodily disturbances and so-called * hys- 
terical' symptoms. When one movement system completely 
inhibits another which involves antagonistic movements, if 
the inhibited system is small, we may suppose that the 
comparatively insignificant amount of energy which is thus 
dammed up finds inconspicuous channels for its escape. But 
an emotion, with energy enough to involve the whole muscu- 
lar system, must when inhibited send its energy out with 
more general disturbance : it cannot merely leak away. 

The case of automatic writing (5) is a peculiar one. One of 
the best examples recorded by a trained psychologist is that 
furnished by Patrick's * Henry W.,' reported in volume five of 
The Psychological Review (104). Here, during many successive 
sittings, the hand of the subject, whose attention was engrossed 
in reading, wrote long series of answers, more or less coherent, 
to questions asked in a low tone. The complete separation of 
the systems of movement performed by the hand from the 
systems concerned in the reading was indicated by the entire 
failure of * Henry W.,' on being diverted from his book, to 
recognize anything that he had written. In other similar cases 



226 MOVEMENT AND MENTAL IMAGERY ^ 

it has been shown by the fact that the subject cannot feel pin- 
pricks on the hand. Sidis (128) reports a case where the pa- 
tient, engrossed in reading, made no remonstrance on having 
the writing hand pricked, but the hand immediately wrote, 
" Don't you prick me any more." 

Now, the first thing to be noted, I think, about automatic 
writing is that it involves the simultaneous operation of sys- 
tems which need not contain any incompatible movements, 
although in an ordinary subject they would do so. The *self ' 
that does the writing involves hand-movement systems and 
systems connected with the ear: this self is talked to, and re- 
sponds by writing. The *seK' that is reading involves eye- 
movement systems, and whatever systems are concerned 
with the ideas suggested by what he reads. It is conceivable 
that these two sets of systems, the eye-meaning systems, and 
the ear-hand systems, may go on side by side without inter- 
ference, because they employ wholly different sets of muscles. 
The greatest chance for interference would come if articula- 
tory movements were concerned in both sets, and they cer- 
tainly would tend to be concerned in the case of the great 
majority of persons. Good subjects for automatic writing are 
rare. In most people, the movement systems set up by the 
reading and those involved in listening and writing would be 
so large that they would necessarily interfere with each other 
by containing incompatible movements. There is no way of 
explaining why this does not occur in such subjects as * Henry 
W.,' except to say that in certain individuals movement systems 
tend naturally to be restricted in their range, and perhaps to add 
that in good subjects for automatic writing the articulatory move- 
ments are of less importance than in the majority of individuals. 

We come now to the remarkable phenomena of dissociation 
as a result of the hypnotic trance. As with so many other 
subjects discussed in this book, our aim will be merely to indi- 
cate a few suggestions as to the direction in which an explana- 
tion for these phenomena may be sought consistently with 
our general motor theory. 



DISSOCIATION 227 

What, in the first place, is normal sleep? Nobody knows. 
But the hypothesis as to its nature which best fits the general 
theory of this book is certainly that recently maintained by 
Shepard (125). "Sleep and sleeplessness," he says, '*are men- 
tal processes." "Sleep is promoted by the situation in which 
we have really become accustomed to sleep." "Sleep is con- 
trolled by conditions similar to those which control attention 
generally." "As we go to sleep, then, we become absorbed in 
a mass or complex of fatigue sensations. These tend strongly 
to inhibit other processes, especially motor activity and con- 
sciousness of strain sensations in the muscles." 

Translating these statements with little difficulty into 
terms of our own theory, we should say that sleep is a move- 
ment system. The apparent absurdity of this statement van- 
ishes when we take the words * movement system ' in the broad 
sense, as including static as well as phasic systems. Sleep is 
a static movement system, an attitude. It is an attitude, as 
nearly as we can judge, of complete relaxation, the inhibition 
of any muscular contractions whatever. This attitude, like 
any other movement system, is brought about by the opera- 
tion of associative dispositions. It is suggested. When all the 
surroundings are favorable, including the external surround- 
ings, the quiet of the sleeping room, and the internal sur- 
roundings of fatigue stimuli, then the attitude of sleep is 
produced, just as a name is recalled when the associative dis- 
positions leading to it are set into action. Now, if sleep as an 
attitude is complete muscular relaxation, perfect sleep will of 
course be unconscious, because consciousness is dependent on 
motor contractions. Imperfect sleep, however, is an attitude 
of incomplete relaxation. In imperfect sleep, various stimuli 
from outside and inside the organism, aided by perseverative 
tendencies, may set up movement systems, limited in scope, 
which are the basis of dreams. It is the limited and fragmen- 
tary character of these systems, liable as they are to inhibition 
at any point by the maintenance of the relaxed attitude of 
sleep, that is responsible for the fragmentary and incoherent 



228 MOVEMENT AND MENTAL EMAGERY 

character of dreams. There is reason for thinking that move- 
ment systems which have been initiated during the day, only 
to be inhibited by incompatible systems, have a special tend- 
ency to recur in dreams. Every one who is interested in re- 
calling and studying his dreams must have noticed the fact, 
emphasized by Delage (28), that their material can be traced 
to impressions of the preceding day which were barely noticed 
at the time of their occurrence, because they did not fit into 
the train of thought at the time. Possibly the reason why 
these reappear in the dream content, rather than the move- 
ment systems which have been fully developed, the basis of 
those thoughts which have been our main occupation, is that 
having been set in readiness by the previous day's experience, 
they are yet imaffected by the fatigue processes which tend to 
substitute relaxation attitudes for all the more fully exercised 
systems. 

In sleep that is not profound, certain thoroughly organized 
and long established systems may escape the influence of gen- 
eral relaxation and modify such recurrent and perseverating 
systems as occasion dreams. It is in this sense that we may 
understand Freud's (38) conception of a * dream censor,' a 
representative of the waking self that will not permit cer- 
tain dreams to occur, at least without modifying and trans^ 
forming them. The most firmly rooted 'habits' and 'instincts' 
— that is, the best established movement systems — may thus 
repress and modify the fragmentary dream systems in so far 
as the latter contain movements incompatible with those of 
the habits and instincts. The Freudians, however, overlook 
the fact that precisely the same kind of transformation may 
result from purely temjwrary organic systems. A slight attack 
of indigestion may set into activity during sleep a movement 
system identical with that produced in terror, and in such a 
case a perfectly harmless object that is being dreamed of may 
become transformed into a frightful one: a small dog may 
grow into a lion with which one is desperately struggling. I 
have often exi>erienced the sudden transformation of one per- 



DISSOCIATION 229 

son into another in the course of a dream, not by the action of 
a censor, but through the influence of the organic background. 
Thus I may dream of the illness of a member of my family: 
at the moment when the illness results in death the person is 
transformed into a stranger, simply because my organic atti- 
tude during sleep happens to be too comfortable to supply the 
strong emotion that would be called for by the death of some 
one near to me. 

Sleep, then, may be plausibly thought of as a perfectly 
definite static movement system, a bodily attitude of com- 
plete muscular relaxation. This attitude, in going to sleep, 
is assumed first so far as full muscular movements are con- 
cerned: there is lethargy and an 'unwillingness* to move 
which amounts almost to incapacity. Every one is familiar 
with that state of extreme drowsiness in which, while one can 
still hear what is going on around, one's Hmbs feel leaden and 
paralyzed. Later, the relaxation attitude affects even tentative 
movements in all muscles, and when this occurs, of course 
associative activity is completely abolished. During various 
fluctuations in the depth of the sleep, that is, the extent of 
the relaxation, disconnected systems of tentative movements 
may be set into activity, either by outside stimuli or by their 
own perseverative tendencies, and they may interfere with one 
another and modify one another: they are the basis of dreams. 

Now, if some such description as this fits the nature of sleep, 
how shall we conceive the nature of the hypnotic trance? 
Certainly, if normal sleep is an attitude that can be brought 
on by suggestion and the working of associative dispositions in 
the same fashion as an idea is recalled to the mind, hypnotic 
sleep is even more obviously the work of suggestion. The 
essential feature in all methods of hypnotizing is the suggestion 
of sleep: in certain subjects the mere command * Sleep* is suflS- 
cient to send them off. But the essential difference in the sug- 
gestion which brings about normal sleep and the suggestion 
which brings about the hypnotic sleep is this: the former is 
derived from what we may call a diffused source, the latter from a 



230 MOVEMENT AND MENTAL IMAGERY 

concentrated source. A person who goes to sleep at night in his 
own bed gets the suggestion of doing so from all his surround- 
ings, and especially from his own fatigue sensations. It is 
true that the hypnotizer generally arranges the surroundings 
to suggest relaxation, by darkening the room and keeping it 
quiet, but the main source of the suggestion lies in his words: 
* You are relaxed all over; you cannot lift your arm; your whole 
body feels heavy; you cannot move at all.' There are no actual 
fatigue poisons acting on the patient in any quantity sufficient 
to bring about the relaxed attitude of sleep. The result of 
these artificial conditions is that the patient is not relaxed so 
far as the operator is concerned. To the operator's words 
he is all attention; to everything else he is relaxed. Every 
movement system that takes its origin in the operator's words 
has complete play, whether it is a full movement, as when the 
operator tells him to dance or sing, or a tentative movement, 
as when the operator suggests that he sees a rose before him. 
Now, by no means every one makes a good subject for the 
deeper stages of hypnosis. Every normal person who does not 
set up in himself an active attitude of resistance will become 
sleepy and lethargic under the operator's suggestions to that 
effect, and is likely to find it hard or impossible to move a limb 
when its immobility is suggested. The * lethargic' stage was 
thought by Charcot to be the initial stage of the hypnotic 
trance. But the * somnambulic' stage, where negative sugges- 
tions such as 'You are relaxed,' or *You cannot move,' give 
place to positive ones, such as, *You are swimming,' or *You 
see a glass of water on the table before you,' is not obtainable 
in nearly so many observers. The reason why some i>eople 
enter it so much more readily than others is clearly related 
to the reason that makes some people display the phenomena 
of automatic writing so much more readily than others. The 
lighter stages of hypnosis demand an effect that is spread over 
all the organism, general relaxation, or even general rigidity. 
But the deeper stages demand that there shall be activity in 
certain restricted movement systems and relaxation elsewhere. 



DISSOCIATION 231 

This means the possibiHty of smaller systems than are charac- 
teristic of the motor mechanism of the majority of persons. 
We cannot escape the conviction, since there exist such strik- 
ing differences among individuals as regards their readiness to 
become hypnotized and to display the phenomena of auto- 
matic writing, that an important factor among others in bring- 
ing about dissociation, or the failure of associative dispositions 
to function normally, is an individual peculiarity of cortical 
organization, according to which there is a natural tendency to 
form small rather than more extended movement systems. The 
process of hypnotizing a person does not produce this char- 
acteristic; it merely gives it a chance to exhibit itself. The 
tendency to small movement systems would naturally be en- 
couraged and developed by the frequent experiencing of con- 
flicting emotions; that is, of large and complex movement sys- 
tems having incompatible elements. The mutual interference 
thus generated would tend to prevent the occurrence of large 
movement systems in general, since any large system would 
be apt to call up the opposed emotions. Thus such conflicts 
between strong innate tendencies have a peculiar liability to 
produce dissociation, alternating personalities, and the more 
marked phenomena of hypnotism; the movement systems in 
such a case become small and restricted for much the same 
reason that two persons passing on a narrow footbridge make 
themselves as small as possible. 



THE END 



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151. Whipple, G. M.: An Analytic Study of the Memory Image and 

Process of Judgment in the Discrimination of Clangs and 
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13, pp. 219-368 (1902). 

152. Witasek, S. : Beitrage zur Psychologic der Komplexionen. Zeit. 

f. Psych., Bd. 14, S. 401-435. 1897. 

153. Witasek, S.: Ueber Lesen und Rezitieren in ihren Beziehungen 

zum Gedachtnis. Zeit. f. Psych., Bd. 44, S. 161-185, 246- 
282. 1907. 

154. Wohlgemuth, A.: Simultaneous and Successive Association. 

Brit. Jour. Psych., vol. 7, pp. 434-453. 1915. 

155. Wolfe, K. H.: Untersuchungen Uber das Tongedachtnis. Phil. 

Stud., Bd. 3, S. 534-571. 1886. 

156. Woods, E. L.: An Experimental Analysis of the Process of 

Recognizing. Am. Jour. Psych., vol. 26, pp. 313-387. 1915. 

157. Woodworth, R. S.: Imageless Thought. Jour. Phil. Psych, and 

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REFERENCES 243 

158. Woodworth, R. S.: A Revision of Imageless Thought. Psych. 

Rev., vol. 22, pp. 1-27. 1915. 

159. Wreschner, A. : Die Reproduktion und Assoziation von Vorstel- 

lungen. Zeit. f. Psych., Erganzungsband 3, 1907-9. 

160. Wundt, W.: Grundzuge der physiologischen Psychologic. 6*® 

Auflage, 1911. 

161. Ziehen, T.: Introduction to the Study of Physiological Psy- 

chology. Translated by C. C. van Lieu and O. Beyer. Lon- 
don, 1892. 

162. Ziehen, T.: Die Ideenassoziation des Kindes. Sammlung von 

Abhandlungen aus dem Gebiete der padogogischen Psychol- 
ogic, Bd. 1, Heft 6 (1898); Bd. 3, Heft 4 (1900). 



INDEXES 



INDEX OF SUBJECTS 



Ability, general, 168. 

Action theory, 21 /. 

Activity attitude, 114, 135, 161/., 179. 

Actual moment, 159/. 

^Esthetics, 184. 

After-image, memory, 62 jf., 107, 110 

/., 120/., 153. 
After-image, retinal, 62 Jf., 84/. 
Aids, 109, 112, 133, 136/. 
All or none principle, 58. 
Animal intelligence, 59/., 132. 
Antagonistic movements, 3/., 15, 

23/., 30/ 
Articulation, movements of, 46/., 59, 

128. 
Assimilation, 79. 
Association of movements, 6/. 
Association pathways, 33. 
Association time, 90/., 114/., 123/. 
Associative co-excitation, 125/. 
Associative dispositions, 88/., and 

passim. 
Attention, 21/., 34/., 44, 56/., 60, 

64/, 75, 104/, 108, 112/., 118, 

124/., 133, 197/. 
Attitudes, 47, 84, 158/. 
Attitudes, conscious, 189/. 
Attitudes, latent, 173. 
Aufgabe. See Problem Idea. 
Automatic writing, 221, 225/. 
Awareness, 191/. 



Complex (Freudian), 224/. 
Condensation of images, 217. 
Consciousness, 17/, 30/ 
Constellation, 142, 158. 
Contradiction, feeling of, 198/., 209, 

220. 
Corresponding points, 41. 
Cortex, organ of tentative movements, 

60/. 
Creative thought, 182/ 

Desire, 160. 

Determining tendencies, 152/. 
Difference, feeling of, 200/. 
Diffused movement systems, 198/. 
Discrimination, based on movement, 

43, 48/ 
Dissociation, 221 / 
Distance receptors, 59. 
Distraction, 76, 133/. 
Distributed repetitions, 112, 117/. 
Double images, 41 /. 
Dreams, 227/ 
Duration, feelings of, 207. 

Efl5ciency of mental work, 167/. 

Effort, 134/., 161/ 

Emotion, dissociating influence of, 224. 

Expectation, 201/. 

Extension of concept, 213/ 

Eye movements, 14/., 46, 59. 



Behaviorism, xiii/. 

Bewusstseinslagen. See Attitudes, con- 
scious. 
But, feeling of, 186/., 198/., 202/. 

Causality, 209/. 

Centrally excited sensation, 28/. See 

Image. 
Certainty, 66, 203. 



Facial movements, 45 /. 

Fallacy, 178/. 

Familiarity, feeling of, 187, 193, 203/ 

Fatigue, 58, 86, 114, 159, 165/, 179/. 

Final common path, 4, 33. 

Finger movements, 45. 

Forced associations, 124, 171. 

Form qualities, 188, 194. 

Free associations, 123/., 171. 



248 



INDEX OF SUBJECTS 



Frequency factor, 120/. See Repeti- Mind reading, 54/. 

tion. Movement sets, 16, 156/., 213/. 

Fusions, analysis of, 41, 197/. Movement systems, 10/., and pa«- 



Ilabit, 36, 51. 

Helps, method of, 106. 

Hypnosis, 221, 226/ 

Identical Series, method of, 101 /., 110. 

Illicit process of major term, 181. 

Illicit process of minor term, 180/. 

Images, memory, 27/, 49/, 146/ 

Imageless processes, 43, 185/ 

Imagery, kinsesthetic, 49 / 

Imagery types, xii, 43/. 

Imagination, 146/., 183/. 

Incompatible movements, 24, 123, 
128, 130/, 134, 179/, 203, 210/, 
215, 224/, and passim. 

Incorrectness, feeling of, 202. 

Indeterminate order, movement sys- 
tems of, 12. 

Inhibition, 3, 24/, and passim. 

Inhibition, effectual, 94/., 123/ 

Inhibition, generative, 94, 123/ 

Inhibition, retroactive, 126. 

Intension of concept, 213/ 

Intensity, 37/, 78, 205/ 

Intentional movement sensations, 51 /. 

Interest, 135. 

Interference of associative disposi- 
tions, 122/ 

Introspection, 18/, 26, 39, 49/., 197 
/, 216, 217. 

Irreversible movement systems, 12. 

Judgment, 174/ 

Kinsesthetic processes, 10, 31/, 38, 43/., 
48/, 194/, 217/, and passim. 

Language, 132/. 
Length of series, 108/ 
Likeness, feeling of, 200/, 203/. 
Location of visual images, 146. 

Meaning, 83, 141/, 191/, 219/. 
Memory span, 74/ 



Muscle reading, 54. >v\u,^<^c ^vtt*yt ^ t^o 

Namable imageless processes, 195/ 
Non-antagonistic muscles, 22/. 
Non-sensational processes, 197/ See 
Imageless processes. 

Organic movements, 47. ; 
Organic sensations, 38/. 
Overlearning, 112, 116. 

Part Method, 117. 

Perception, 98/, 130/. 

Peripherally excited sensations, 30. 

Perseverance, 87. 

Perseveration, 77, 84/, 93, 94, 120/. 

125, 147/., 154, 166, 227/ 
Persistent tentative movements, 

156/ 
Phasic movement systems, 11. 
Place associations, 103, 138/ 
Practice, 170. See Repetition. 
Prepotent movements, 3, 7. 
Primary memory image, 70/. 
Problem idea, 110/., 114, 135, 151/, 

176/ 
Proprioceptive reflexes, 9. 

Reaction experiments, 69, 151, 170/. 
Readiness, 82/., 120/, 143, 170/, 

213/, 222. 
Reasoning, 174, 177/ 
Recall, effect of. 111/, 126/, 163. 
Recency factor, 120/., 124/ 
Recognition, 83, 98/., 101 /., 106, 108, 

203/ 
Reconstruction Method, 102/, 106, 

110. 
Recurrence of movements, 72/ 
Reflexes, 1/ 
Relational element, 187. 
Relational feelings, 185, 187, 192/ 
Repetition, effect of, 104/, 124/. 
Resolve, 159/ 



INDEX OF SUBJECTS 



S49 



Reverse associations, 83, 92, 144. 
Reversible movement systems, 13/. 
Rhythm, 86/., 136/. 

Saving Method, 95/., 104, 115, 119. 
Scoring Method, 106, 114, 119. 
Simultaneous movement systems, 

11/, 128/., 179, 209/. 
Sleep, 227/ 

Spatial relations, feelings of, 207/. 
Spatial systems, 14/ 
Special Determination, Law of, 170/ 
Static movement systems, 11. See 

Attitudes. 
Strain signals, 60. - 

Subliminal associative dispositions, 

90/, 95/., 103, 108, 125. 
Subordination, logical, 212/ 
Successive movement systems, 11/., 

31/, 5Q. 
Surprise, 198. 
Synaptic resistance, as conditioning 

consciousness, 20/. 



Tendency, feelings of, 186, 191. 
Thought elements, 188, 192. 
Time, effect on associative disposi- 
tions, 97, 114/. 
Transitive states, 185/. 

Uncertainty, 203. 
Undistributed middle, 180. 
Unexpectedness, 198, 201/. 
Unnamable imageless processes, 205, 

215/ 
Unpleasantness, 7/., 166/, 223/. 
Unrest attitude, 164/. 

Value quality, 195. 

Whole and part, 212/. 
Whole Method, 117. 
Will, 164/ 
Wrong associations, 93. 

Zero cases, 98. 



INDEX OF NAMES 



Abramowski, 71. 

Ach, 51/., 69, 81, 95, 128, 151/., 159/,, 

169/., 191/., 193. 
Alexander-Schaefer, 76. 
Angell, xii. 
Arnold, 144. 

Balaban, 143. 
Baldwin, B. T., 135. 
Baldwin, J. M., 147. 
Beaunis, 50, 196. 
Bentley, 79. 
Betz, 47. 
Bigham, 102/. 
Binet, 74. 

Book, 113, 120, 162. 
Bourdon, 74, 123. 
Brown, 58. 
Biihler, 192/., 216/ 

Calkins, 63/., 124, 187/. 
Cattell, 123. 
Charcot, 230. 
Claparede, 155. 
Cordes, 91. 
Cornelius, 188. 
Creighton, 182. 
Cumberland, Stuart, 54. 

Daniels, 70, 76. 
Delage, 228. 
Diirr, 192. 

Ebbinghaus, 83, 95, 97, 107, 110, 115/., 

117, 122, 205. 
Ebert, 68, 137. 
Ehrenfels, 188. 
Ephrussi, 98, 106, 108. 
Exner, 70. 

Fechner, 62/ 
Fernald, xii. 



Finkenbinder, 116, 122. 
Fischer, 102, 106, 108. 
Freud, 223/ 

Galton, 74, 90. 
Gamble, 102/, 106, 110. 
Goldstein, 81- 
Gordon, 136/., 140. 
Groos, 153. 
Griinbaum, 169. 

Harter, 112, 162. 
Hawkins, 107. 
Hayden, 200. 
Head, 60. 
Hirszowicz, 124. 
Howe, 133. 
Hume, 185. 

Jacobs, J., 74. 
Jacobs, W., 140. 
James, xii, 32, 50, 185. 
Jost, 117/. 
Judd, xiii. 

Katzaroff, 111, 163. 
Knors, 106, 110. 
Koffka, 173, 218. 
Kostyleff, preface. 
Kulpe, 189, 192, 216/. 

Ladd, 116. 
Lange, xiii. 
Lankes, 87. 
Lay, 81. 
Lehmann, 76/. 
Leuba, 78, 148. 
Levy-Suhl, 135. 
Lewis, 148. 
Lipmann, 119. 
Locke, 190. 
Loeb, xi. 



INDEX OF NAMES 



McDougall, xiii, 144/., 219. 

Mach, 188. 

Marbe, 174, 189. 

Martin, 81, 146. 

Mayer, 189. 

Meakin, 80. 

Meinong, 188. 

Messer, 190/. 

Meumann, 68, 110, 137, 155, 160, 183. 

Meyer, 128/. 

Michotte, 143. 

Milhaud, 146. 

Montague, 20, 25. 

Moore, 81 /. 

Muller, 69, 74, 82#., 92, 94, 98, 114, 

116, 123, 125/., 130, 137, 139/., 

141/., 154, 193. 
Miiller-Freienfels, 47. 
Munsterberg, xiii, 21/., 37, 123, 194. 
Murray, 80. 

Nagel, 107/, 140. 

OfFner, 131, 154. 
Ogden, 143. 
Ohms, 99/. 
Ordahl, 133. 
Orth, 189, 195. 

Pappenheim, 94. 

Patrick, 225. 

Pawlow, 7. 

Perky, 146/. 

Peterson, 136, 140. 

Pfungst, 55. 

Phillippe, 148. 

Pilzecker, 84, 92, 94, 98, 114, 116, 123, 

125/., 130, 140. 
Pohlmann, 106. 

Poppelreuter, 75, 126, 136, 222. 
Purkinje, 64. 

Radossawljewitsch, 81, 110, 115/., 

122, 143. 
Ranschburg, 123. 
Reuther, 101, 106/., 110. 



Ribot, xiii. 
Rousmaniere, 65/. 
Russell, 60. 

Schaefer, A. A., 8. 

Schaefer, W., 153. 

Schaub, 38, 40. 

Schumann, 83, 92, 125, 187, 139, 

143. 
Scripture, 133. 
Shaw, 78, 148. 
Shepard, 227. 
Sherrington, 59, 127. 
Smith, G. W., 106. 
Smith, M. K., 137. 
Spearman, 168. 
Spencer, 187. 
Steffens, 116/. 
Stout, 38/, 147, 186. 
Strieker, 50, 54, 57, 197. 
Sybel, von, 134. 

Tarde, 182. 

Titchener, 52/., 85, 194, 197/., 205. 

Toll, 135. 

Trautscholdt, 90, 92. 

Urbantschitsch, 67. i 

Vaschide, 138/. 

Warren, 78, 148. 

Watson, xii. 

Watt, 151, 154, 177. 

Weber, 110. 

Wells, 123, 171. 

Whipple, 77/., 79/., 200. 

Witasek, 106, 111, 188. 

Wohlgemuth, 131. 

Wolfe, 77, 79, 200. 

Woods, 53. 

Woodworth, 116, 188, 195, 215, 218. 

Wreschner, 171/. 

Wundt, 90, 195, 207. 

Ziehen, 38, 40, 84, 142. 



CAMBRIDGE . MASSACHUSETTS 
U . S . A 



